Here:
http://www.sonycreativesoftware.com/vegaspro/compare is a comparison of the different Sony packages. Unless you know exactly what you are going to do and do not intend to use it for producing DVDs avoid the basic "Movie Studio".
The Platinum version gives you everything you might want from a "basic" NLE and DVD authoring suite.
Consider the Suite if you want some free production music, an audio editor (here we're talking about something to edit individual audio files, not adding effects and mix which Movie Studio does brilliantly anyway - Vegas was originally an audio program), and a bunch of effects. It's good value. If you don't want these though, save yourself £30.
For me SoundForge Audio Studio (the audio editor) was rather limited - unlike the full SoundForge Pro, which is fantastic (and pricey) and GoldWave (cheap) or the free Audacity were better featured.
If you go down this route and want more in the future, Vegas Pro is identical - just with "more", so there's no re-learning.
Sony Movie Studio is called just that - they dropped the "Vegas" at the last release, but this was just to avoid confusion - it's the same product, just missing a few things.
Please do try it and take time to work through the interactive tutorials. I moved from Pinnacle Studio to Vegas Movie Studio in 2006 and found Vegas very straightforward. Others find it complicated. I don't think it is because it is simple/complicated - I think it just depends on how one's brain is wired. It can seem daunting to some as so much is visible as opposed to being hidden away, but it makes everything so much more accessible once one become familiar.
I'd also recommend you try Adobe Premiere Elements (also free downloads available) which did not appeal to me.
I'm happy to (try to) help out if you get stuck with Sony Movie Studio.
