You can use any 2.5 drive with the PS3 as long as its standard (those extra 3 platter 2.5 1TB drives are incompatible.)
What I would recommend is a 640GB drive like the WD Scorpio 2.5 which is only about 90 bucks US (which is around 50 pounds give or take on the exchange rate). It is REALLY easy to back up to an external drive or us a friends PS3 to transfer all your data (including "can't copy" saves) to the new drive.
I mainly suggest going with the 640 because of the play TV thing, if you are recording a lot of TV you're going to want that extra room. I tend to also move movies from my computers hard drive to the PS3 and leave them there for storage so that gives me use for the extra space too.
As to fast hard drives like 7200 or even 10000+ RPM drives and SSDs they all increase the speed of the PS3, especially when loading games that have an install, but they're not usually worth it unless saving 5-10 seconds every hour or so really matters that much to you.
PSN ID: ChosenOne feel free to add me
