Another vote here for the two rod "pleasure fishing" approach - i.e. i'll fish one rod on standard float gear and the other with an avon rod on an alarm, usually with a method feeder, ideally for larger fish (tench, carp, bream).
That said, i will cut my cloth according to what's in front of me... if i'm sure that all i'm going to catch on the float set up is roach, perch, rudd etc - then i'll likely go with a 3lb bottom, a size 16 or 18 and maggots. However, if i thought i had a realistic chance of a carp or tench on the float then i'd probably go up to a hooklength around 5lb and size 14 or 12.
As has been mentioned, you can land larger fish on float gear ok.... going back a while, i never fished for carp other than float fishing, and for a long time my PB was a 12lb fish that i landed on 4lb line. The biggest point of technique to learn about when playing a big carp on light gear is the angle of the rod, relative to the fish... you need to keep the rod low to the water and apply side strain to the fish, not stick it up in the air. You can get the fish in relatively easily like this (also works with barbel and chub). The other thing is just to be realistic about your drag setting, and understand that a fish taking line is no bad thing (actually its always been one of my favourite features in playing a carp!) My view point on the drag is that you'll always have a chance to tighten it up, but you'll only know its too tight when a fish is lost - so ere on the looser side.
Of course, that doesn't really work for fishing near snags, but in that case you probably shouldn't be approaching that swim with float gear!
Then of course there's rivers! Have you got any close by?
