I'm not sure what qualifies as inexpensive for you - I use Corel Video Studio Pro and I'm pretty darned happy with it. You can download an unrestricted (except for being limited to 30 days) demo to try it out. If you like it, it's $49.99 to purchase the license.
It will do everything you're asking plus a lot more (video in video, overlays, titling, etc.). I'm just beginning to scratch the surface. If you're going to do really complex audio editing you might want to do that separately in something like Audacity (free open source audio editing software) because I think that Video Studio only supports three audio tracks and it doesn't seem to support panning between the stereo channels. If it does, I haven't discovered how, anyway.
John