Always buy the best you can afford, simply to avoid dissapointment, so that later, when you need a function that you haven't got you need to start hunting for other solutions.
The lower price range Vegas products are extremely good value for money though and will normally suffice for above basic functionality.
But remember at the end of the day they are all tools, I got old that once; and to an extent they were quite right.
Pro editing software is all good but it wont make a film any better if you dont know how to use your film making tools so to speak. And its a lot of money for not a lot of editing difference if your just using the basics
I say this because when I was a skint Student, but was desparate for editing software I was hell bent on getting adobe premiere pro because it was pro. However someone told me about the consumer version, Elements and I tried it and I never looked back. Suited me for everything
Pro software costs a lot of money and it is a recession, but if you can justify the spend then go for it man cos its full of cool extras.
Then again I now have Premiere pro now so maybe I sound like a big hippocrite HA!
Buying one of the Movie Studio versions and later upgrading to Pro is not significantly more expensive than buying Pro in the first place - indeed if you happen to get the correct offer (being in the right place at the right time) it could even work out cheaper.
Pro IS Movie Studio with additional facilities. (Alternatively MS is Pro without some facilities). 4 Video + 4 Audio tracks is plenty when getting to know a product. So, any time spent learning how to do things with MS IS time spent learning to do things with Pro. If you really don't get on with Vegas, then you haven't wasted big bucks.
But then why bother buying? Download the free, fully functional, 30 day trial - maybe of MS and later, once you're familiar with that, Pro (you can import MS project files into Pro but NOT the other way round - so be careful of that)
So you can have 2 months of working in different flavours of Vegas before you need to shell out anything and you'll be much better informed then than any number of posts here will make you.
Thank you all for your replies they are very helpful.
If I want to be utilising masks and (for one idea I have currently) there will be an effect in some ways similar to the "Schindler's List" or "Sin City" effect of blocking out all colour except one. I'd need pro for all this wouldn't I?