Any router should work but, because it's the router which connects to the internet (and not your PC which does so), it would make sense to get a well-known make. That's because you'll need to get the information from Tiscali (either online or over the phone) telling you how to set it up; that could prove difficult if you get a router they've never heard of.
You state that you don't need anything which is 'top of the range' but you then refer to watching movies. Video streaming requires higher broadband speeds, with greater reliability, than almost any other use of the internet. Many people would suggest that you should buy an 'N' rated router for video streaming; the problem is that they tend to be rather pricey. In practice, as long as you're getting good broadband speeds through your phone line, a 'G' router should do the job.
Belkin routers are well-known. (So every ISP should be able to tell you how to set one up). They're also cheap at Tesco. This is what I use:
http://direct.tesco.com/q/R.204-9902.aspx
Chris