Well, for starters the Tascam US series is a great way to begin. You may even want to look into the US-428 which has 4 inputs and even a mic pre built into it as well.
If you are planning on using phantom power microphones(condensors) then you will need a phantom power supply, which are very affordable!
If you want to dive into the computer based recording systems that's cool but you may want to look into a stand alone recorder such as the Tascam 728 I think it is? It records onto an internal hard drive and you don't have to deal with the computer OS interupting it or troubleshooting if it doesn't work properly.
What sort of a budget are you looking into and if you are going to use your computer at home what are the specs? This way we can determine if it's even worth you going that route.
If you only plan on doing a few tracks it shouldnt matter but eventually you will get hooked(as we all have! :D