24p provides a smoother picture, try watching a scene with a long slow panning shot & you should see a difference with/without it, there's a thread about it somewhere round here ... (sorry I don't have time to look for a link for you, or have a look at this
wikipedia article).
Are you living in the UK? This is an American based/centric forum, so while you could get some good pointers as to what to look for for a sound system (have a look in the
Home Theater Gear sub-forum, if you check through the first 3 or 4 pages you should find plenty of relevant threads) I'd check out a UK forum for more specific info, try
What Hi Fi to start with.