For me... it depends on how long the queue is. If say, i'm behind 2 or 3 cars at the lights, i don't bother to filter, but if it's a looooooooooooonnnnnnnnnnnnnng queue up to a roundabout then, hell yea, i'll filter.
Filtering on the right is usually better than filtering on the left, mainly because drivers tend to use their right mirrors more than their left, and also because pedestrians tend to hop out of cars on the left (leaving you subject to a dooring!). however, you must keep an eye for cars swapping lanes (good indicators they are going to do this is their indicator signals and their front wheels being turned to the right) and you need to also watch out for them letting traffic in and out of side roads (watch the gaps). If large vehicles come the other way, and you think it's gonna be a bit of squeeze, just pull up between cars to let it pass (you may not be able to get right in between but there is more option to pull further in there even if there is not enough room to get your bike fully in).
As said before, all the cars don't move off together. The worse thing you can do is suddenly stop when they start moving as this confuses the driver and may cause him to pull up sharply; keep your speed and line, its likely that you will first of all be moving next to a car but as he pulls away from you, you will find an appropriate gap opens up behind him, indicate you are moving back in by turning your head and getting eye contact, signal if necessary. When filtering long queues I don't worry about gaps being open nearer to the roundabout as there are normally plenty to take when you get up there, as that's where the bigger gaps occur anyway, as one car speeds off, the others don't react immediately. If there aren't any gaps, wait by the side of a car, say 2 or 3 cars back, and look at the driver in the car behind to indicate your intention to come back in and take primary.
if you choose to use cycle lanes leading up to lights, ensure you are not in someone's blind spot when you get to the front. go past the cycle lane and occupy the ASL (advanced stop line) in primary position (where the car is). If there is no ASL, sit in front of the car so they can clearly see you, preferably in primary. This is where you use your common sense whether to filter. Filter if you think you have time (one of the things my driving instructor told me is that if the light is already on red, expect it to be green by the time you get there, and vice versa... so if you have only seen the light on red as you approach, its more than likely gonna turn green before you get to the front. However, if you see it go from green to red, you're more likely to get to the front before it turns back to green). As said, if i'm only 3 or 4 cars behind, i tend not to bother to filter, i just stay in primary (out of the cycle lane) and go through with everyone else. only if there is a long queue will i filter. i just don't see the point of filtering past two cars to take primary, then hold those two cars up going across the junction which is bound to just annoy them as they will feel like i pushed in (although i have every right, i just don't see the point when they are faster than me anyway, as i only inconvience myself by forcing them to again overtake me). anyone who pulls up behind me while i'm in the queue though is just fair game. they are just in the same queue as me. Great British tradition,... join a queue. no one minds your presence in front of them.
Take extra care filtering HGVs. presume they can't see you at all, and don't filter up and sit on the left at junctions. plenty of cyclists wish they hadn't done that. some don't wish at all, because they no longer can. drivers are human, they may forget to indicate, so don't presume you know where a HGV is going.
if you don't want to filter, no one is forcing you to, just scoot along in the queue, but do it in primary position.