Schumachers and Xrays are probably most popular. For about £100 - £120 you can get a new MI1 or a good used MI4.
Tamiya TRFs are also really good - very expensive when they first came out but can be had for a steal these days (shameful plug!):
http://www.ebay.co.uk/itm/1613935302...84.m1555.l2649
The Hobao H4e is also an up and coming star at the moment - £200 brand new or about £120 used. I've just bought one from a fellow Oopler and will be racing it in a couple of weeks, 17.5t blinky.