Just to add my 10 cents worth for what you are doing Vegas, FCP 7, FCP X and Premiere will all do (I have used Vegas, FCP 7 and Premiere quite a lot and did have a play with FCP X).
I do some long form stuff so dont like Vegas as it does not have sequences. You can nest projects and have several open at once but this is a pain when you have more than a hand full of sequences. Also a lot of peole are using sequences rather than bins as it allows footage to be easily found (you can put all your 'beach at night' shots in one sequence and scrub thought all the footage to find what you want).
What is great about Premiere is the After Effects/Audition roundtrip. It is also used more by facilities houses than FCP X so this may affect the work you get (Premiere is now considered one of the big boys with Avid and FCP so it is becoming a industry standard).
Platform is a bit of an issue. Obviously with FCP X you need mac. Premiere does run on both Mac and Windows but performs slightly better on Windows. I have a dual boot Hackingtosh, I was first using Mac but switched to windows as it was not playing smoothly.
I personally thinks mac is overpriced (I did previously have a macpro but upgraded to a windows box) and with thre new laptops you cant even change the batteries which is taking the piss IMHO.
So I think my answer is Windows/Premiere Pro (Get production Premium package which has After Effects and audition).