I want to earn a living doing something thats long term, strong and has plenty of opportunities. I'm a college student,btw.
1. PHP - there's tons of resources and scripts to play around with (open source) 2. Scripting w/ Javascript and Ajax
Ruby on Rails - relatively new programming language/framework but it is powerful and easy to learn; you can create complex web apps quickly.
Alternatively if you like Ruby there are two ports of it for .Net (IronRuby and Ruby.Net from memory) A lot depends if your living is working for corporations in which case you need a corporate standard language or if it is to be self employed/ run your own company in which case you can choose any language but be aware of its strengths/ weaknesses in these markets.
AstarothSolutions comment that .Net 2.0, 3.0 and 3.5 are cross compatible with each other, that they have simply added more to it rather than changing the underlying elements, is spot on. Don't think of it as learning a new language/programming environment with each version. And, once you start with one version, you don't have to change to a more recent version if you don't want to. The incentive to change to a newer version is that the newer version has new features. But if you're content with something you've developed in a previous version, you can just leave it alone.
I would start with PHP or .NET - they are probably the easiest to get into in terms of setting up a local development enviroment. Personally I prefer c# over vb in .net. You will quickly realise when you have done one or two languages for web stuff, that they are all very much the same As the underlying protocol of the web isn't changed, there is not very much different in the languages. Should you become happy in PHP and C#, you will find adding java/j2ee, ruby, python, etc really quite easy.
I strongly disagree that PHP is not a "Corporate" language. I have developed websites for companies that Gross 65M plus using pure PHP. The issue that comes to mind and into play is "SUPPORT". That's the main issue, with PHP you basically have zero warranty if/when something breaks. Using a language like .NET will allow you to purchase enterprise level support from MSFT. This weighs in heavily on the scope of a single project. It is also the same with operating system. RHN seems to be the only company to offer global enterprise based support. That is why a lot of companies that have gone *nix have chosen Red Hat. We all know RH is not the best but you have to keep your companies best interest as #1 priority and if I get hit by a bus tomorrow the show must go on.