The types of cyclists I usually see on my commute are:
1. The BSO riding chav. On/off pavement, no lights, seat low, hoodie, smoking a fag etc.
2. The MTB 'casual'. Decent mountain bike - not a Dunlop special, basic lights, regular clothes. Not too quick, often takes pavement shortcuts.
3. The Hybrid Commuter. Flat barred hybrid, ok lights, luminuous jacket, fairly slow, doesn't really look much around them, sometimes RLJs.
4. The Classic Rider. Older lady or gent, suit with h-vis vest or tabard, heavy old tourer with dynamo lights, trouser clips.
5. The Roadie. Modern road bike, full lycra. Usually young-ish (i.e. under 40) but with the occasional MAMIL club group.
Now since things have got a little warmer and the fuel prices have gone up, I have seen a noticeable increase in all of the above, however I have also seen the rise of a new type of cyclist usually unfamiliar to me, which I'm now going to make grossly
6. The Old School Roadie - presumably someone who used to be a keen cyclist who's bike has been relegated to the shed for the last decade or two since having kids and needing to drive everywhere. Now the kids are grown up and they've decided to beat the fuel price increase, they've dusted off the old fella, got some new clothes for christmas, and hit the road. Good on 'em!