It really depends upon your budget and what audio formats you wish to support.
If you wish to get full HD audio from your PS3, then you need and amp that can deal with audio from HDMI. There are some fairly cheap AV receivers that have pre-outs (e.g. some of the newer Yamaha amps) and further up the range you could try the Audiolab processor (available for around £850 if you look in the right place). The key issue with looking for HD audio support is that you have to buy new and as such are paying a premium for it.
If you're happy going s/h and aren't too bothered about HD audio (e.g. if you still find yourself mainly watching DVDs), then there's tons of really good bargains around. Ex flagship receivers from Denon and Yamaha can be had for around £300-400, not bad bearing in mind they cost £2000-3000. Additionally, legacy AV processors are dirt cheap too. Just agreed sale on my old Thule unit for under £300. It cost around £1800 when new and is still an ace piece of kit. Up from that, you're looking at options from Bryston (e.g. saw a nice looking SP1.7 going recently for around £700), Lexicon and Meridian.