What's a cheap video editing software that can do all of this?

Windows? Mac? Linux?

You want a lot. But see how much Avidemux helps. It is open source and free. Read the Wikipedia article here

Or see what you can find on Rapidshare downloads [free but not necessarily legit].

First figure out what program you really want, then try Rapidshare. Make sure you do not get hijacked to a peer-to-peer site. The advantage of Rapidshare is that it polices its servers and keeps virus infections to a minimum. It is only a space broker. You get software from whoever posted it

I haven’t bought a computer yet, but it’s definately not gonna be a mac

A full version of the latest Adobe® Premiere® Elements 8, costs only US$100,-. I have only been using Adobe® Premiere® Pro (CS5 atm), but I hear a lot of good stuff about the Elements version.
You can (and should) always install the free try-out first, see if you like it, then diside if you want to purchase it.

Here’s a review of various video editing software that you might find helpful. All of them fit the description of “cheap” (Under $100)

Imovie can do transitions,text,music…Photobooth is not an editing software it is just taking photos/videos,you can use chroma key there.I dont know for the other features but both application i mentioned is built in a mac

Final Cut Pro is always a good bet.