Well no point in splashing out on a soundcard until you've chosen your motherboard and you know whether it has onboard sound. TBH most of them do have onboard sound now. The Audigy 4 7.1 OEM at £35 is good value though.
Sounds like movies and games is the intended use then, rather than music. In which case you need to decide whether you want 2.0 (stereo), 2.1 (stereo with subwoofer) or 5.1 (5 sats + subwoofer). Obviously a lot of movies and games support surround sound.
If you're happy with 2.1 though, Acoustic Energy Aego M 2.1 Speakers are highly rated for £82. Acoustic Energy are a hi-fi brand so they know how to make speakers. If you want 5.1, things are a bit more tricky cause there's a hole in the market around £100. There's Logitech Z-5400 at £130 which includes digital inputs and a decoder. Below that price there's lots of samey cheap 5.1 systems in the £50-80 price bracket, but none of them really stand out.
Only consider 2.0 if you don't have room for a subwoofer, because they often struggle to produce decent bass.