Long time lurker, first time poster (actually, that's a lie - this is my 2nd post as my first was in the commuting section a few moments ago).
I'm Danny, been commuting to work via bike and leisure cycling for 7 years, started on a BSO mountain bike, bought a Carrera Vanquish[1] in Feb '09 which served me faithfully until I moved to Derbyshire last September. It turns out that a bike with 23mm GP4000s and caliper brakes makes for some brown-trouser moments stopping (or failing to stop) at junctions at the bottom of the peak district hills in the wet. Faced with the choice of a) starting braking 1/2way down the hills to stop in time or b) buying another bike, I went for option b (n+1 and all that) and picked up a Charge Grater 2 purely because it has a wide-range cassette, disc brakes, and the ability to have full mudguards and studded tyres[2], plus was within my budget at the time. Come March I'll be looking for something similar, but with drop bars - forgot how much I hate flat bars!
[1] Yeah, I know, Boo!
Halfords and all that. But with the exception of the handlebars coming loose when I rode it home (!) it actually held up pretty well for many thousands of miles with just the expected replacement parts needed (cassete, chain, brake pads, tyres) and no major mechanicals other than ones caused by me crashing it (gently) occasionally.
[2] Living on the south coast and cycling in urban areas with lots of traffic, I managed to cycle all year round on skinny slicks even in the ice and occasional light snow. Moving to Derbyshire however, ice+hills+twisty, low-trafficked rural roads convinced me to switch to studded tyres for winter.