Your choices are limited. Generally speaking, you get what you pay for. There is supposedly a free NLE for Linux thats pretty good. Free... well I think theres a few NLE's out there just like WMM. But for pro editing, youd be best off to at least get the most inexpensive version of Vegas, Premeire or FCP depending on your system.
That said, many have found success with Ulead Video Studio. This one is very cheap. There is also Avid Xpress (which some like, I never really did), and Pinnacle Liquid Edition. Pinnacle is expensive.
But what you have to ask yourself is... what level am I going to with this? If you want the ability to put 3 clips together and title them, well WMM or its free counterparts may be all you need... CapVHS and VirtualDub to back them up. Or... if you need a bit more pro as I said there is the lesser packages of Vegas, Premeire and Ulead to check out. For pros there is the full Vegas, Premeire, Pinnacle LE to look at. Industry pros use Nitrus and other super high end systems that you'll never be able to afford. Think about how much you are willing to shell out and there will be a package for you.
But my personal suggestion is start with FREE to learn the very basics, even if you only do it for a week. Get a grip on how putting clips together works, adding transitions, and then rendering (ESPECIALLY take some time to learn about codecs and which ones you should use). From there I would suggest downloading a trial copy of each program and finding the one you like the most. But like making a decision on a car, I guarantee there will be some inevitable give/take. Vegas is very intuitive (VERY), but it lacks in a couple of areas. Premiere is very straightforward but has a very steep learning curve. The others all have give/take similar. If you can download a trial before buying, go for it, otherwise, as I said, you have very limited choices in the "free/cheap" range.