It's way under your estimated budget but I got some Superlux HD681 EVOs from Thomann.de (not easily available in the UK it seems) and I really like them. They're a steal at £20 on Thomann too, Head-fi also seems to like them in reviews.
That said, they don't have microphone so if its for games you'd have to splash the rest of the budget on a desktop mic/clipon mic. I'm looking forward to giving them a try with the Soundblaster Z I got from Jonj. They are very bulky however, don't expect them to be portable, but I find them quite comfy even for long hours.
Definitely buy the EVO though, not the other models like the standard 681 or the 668B which are similar, the EVO includes extra velour pads in addition to the pleather pads that most Superlux come with which I found to be absolutely horrid.