It does indeed all start with the choice of fuel, and that is first and foremost determined by where you go and in what climate. I think for third world use, at low temperatures and for larger quantities the multifuel stove is the stove of choice. These are the smelly spidery contraptions connected to a separate fuel bottle by a hose. They are the descendents of the old Primus parafin oil stoves of yesteryear, and of the similar looking petrol stoves. The two important modern innovations have been that these no longer have a large bronze pressure vessel, but use a separate metal fuel bottle. That makes them rather lighter. The second innovation is that almost all of them are now multifuel, meaning that they can use petrol of various kinds (but preferably not car petrol), paraffin oil, or even Diesel (in an emergency). Some new Primus models can even use gas cannisters of the threaded valve type. There are also disadvantages. They mostly do not simmer very well, although some are better than others. They are also a bit smelly because of the fuels you use, and they are fiddly. They are heavier than most alternatives, they clog up with dirty fuel, they need maintenance, and they need to be adjusted while you are cooking. But you can get fuel everywhere, they work a treat at really low temperatures, and they are hot. If you need to melt snow in the Andes, this is the way to go.
Gas cannisters have all the obvious advantages of low weight and convenience. The lightest ones are those that you fit on top of the cannister. They are primarily for solo use in nicer weather. The Snowpeak 100 has consistently come out best in Backpackinglight tests. The biggest disadvantage is fuel availability, as a result of the proliferation of three different types of cannisters. The puncture type are easiest to get, but a bit heavy and clumsy (you cannot disconnect them) and because they are not 100 % safe. Of the valved cannisters there are two types, with the threaded Lindall valve (Optimus, Primus, Coleman and just about everyone), and the click on valved cannisters sold by Camping Gaz. The problem is that in France you cannot really get the threaded canisters, and France is an important destination fo rmany. There are two solutions. The first is to get a multi standard burner, such as made by MSR and now also Primus. The second solution is to get an adapter, such as those made by Edelrid (there are different types, such as puncture to threaded - heavy but useful, or click to threaded, less versatile but lighter). The second problem with gas stoves is their low temperature performance. The solution is what is called liquid feed, where you invert the cannister, and feed liquid gas rather than gas gas. Of course, this demands a different and rather heavier construction with the cannister next to the burner, and connected by a hose. The good news is of course that these stoves are also much more stable, and can use bigger and heavier pots. It is important that such liquid feed can only be done safely (and this is very important) if the the burner has a pre heating loop. Jetboil and others have now also introduced more efficient integrated systems (following in the footsteps of the Trangia), but these are heavy and best suitable for boiling water rather than cooking a real meal. The Primus Eta Express has dangeously high levels of CO emissions.
The third type are the meths stoves. The beauty is that in Europe and the US (HEET fuel line de-icer) meths is almost always easy to get, and cheap. They are also relativley safe stoves as meths does not explode. Meths stoves have no moving parts, cannot get clogged up, or whatever. They are the most reliable stoves you can get, and with a small pre heating cup they will work to below freezing (not at really low temperatures). The central downside is that meths does not contain as much energy as other fuels, so you will use more of it (but you can get it everywhere) and since the flame is not very hot, you need to use it as efficiently as you can. Hence the design of the enclosed stove and windscreen. As a consequence, it is relatively heavy. Trangia have tried to solve this to some extent by introducing a new UL (ultralight version that uses stronger and thinner material, and this has helped quite a bit. So get the UL version (the cut price offers are usually still the heavier models). Trangia have also introduced two additional surface treatments. The first is a teflon coating for non stick purposes. This is heavier and wears, of course. You may consider it for the frying pan (you can buy a new one seperately when it is worn). For the other pots and the windscreen, and perhaps also for the frying pan, there is also the more expensive hard anodized surface. This is also somewhat non-stick, cleans easily, and will last longer. Unless you are on a tight budghet I suggest you take this, with either the HA frying pan or the teflon one, depending on your priorities. The normal Trangia comes in two sizes (forget about the Trangia mini, it does not have the special windscreen). Trangia says the Trangia 27 is for 1-2 people, and the larger Trangia 25 for 3-4. I think that is too optimistic. Unless in a pinch, I would not use the Trangia 27 for two, and similarly, I would not use the Trangia 25 for more than 2-3. I think they are solo and duo stoves respectively. The weight difference is relatively small, but small differences have big consequences if there are enough of them.
Trangia also offer two alternative burners, a 178 gram gas cannister burner for threaded valves (with preheating loop). This increases the weight by only 68 grams, but the gas fuel is lighter. This makes sense in the Trangia 25, but less so in the 27, I think. Trangia also have a multifuel burner. The old one was a special version of the Optimus Nova (but you could also adapt the original Nova) and now a Primus one that can even use gas cannisters. I have the Nova for the Trangia, and occasionally use it in the Trangia 25. It is enormously powerful, and I would only use it in the Trangia 25. It just does not make sense for smaller solo quantities, and I doubt it would get enough oxygen in the 27 (did not try it, however). It makes for a rather heavier set up, of course. My Trangia 25 UL with Nova weighs 240 grams more than the meths Trangia 25. Looking at it differently, using the 325 gram Trangia 25 stand and windcreen instead of the original 125 gram Nova stand (that you remove for use in the Trania) is 200 grams heavier than the Nova without any windscreen. So in this application think of the Trangia as a 100-150 gram heavier but better windscreen than a 50-100 gram sheet of foil. In the Trangia 27 the difference would be even less, of course (50-75 gram), but as I said I doubt if this makes much sense and will work quite so well (any done this?).
The Trangia pots deserve a special mention, because they can be bought separately, and they are great. They are relatively cheap, and weigh as little as your average titanium pots. See
http://www.trangia.s...0eng%202010.pdf Their heat dispersing properties are much better, however. So you could buy a Trangia set, use it when meths seems the best fuel, and use the pots with a small gas stove when you need the lightest gear, or a multifuel stove when that is what you need. If you need the lot, get a Trangia 25 with multifuel burner.
There are also lightweight meths alternatives. Many are very light but not very practical. I think the Clikstand and the Caldera cone are the two most useful ones, as they effectively save you some 200 grams with an alternative windshield. The Clikstand is the heavier one, but I think also the more practical one. A Clikstand with windscreen, original Trangia burner, one pot and one frying pan would be some 400 grams.
I hope this helps.
Willem