Decent (inexpensive) microphone for voice overs

[winds]

(should've got the omnidirectional one though, it was only a little more)

If you're using it for voice overs, definitely the directional one was the way to go. Omni-directional would be a lot more background noise from anything around you. Usually you would be using an omni-directional mic for getting room tones or if you're recording a bunch of singers / musicians at the same time.

[Dave Auto]

Hands down this is the one to get

http://www.amazon.com/gp/aw/d/B003SPVAB ... 03-7497460

It's fantastic. And for like an extra 10-15 bucks you can get a pop filter. Add in something like garage band for audio filters and you are off an running.

I'll second this. Love my Blue Snowball. I usually use it to record spec (test) spots, but many of those turned out sounding good enough to use in regional and national commercial spots (I'm a stage actor who got into doing commercials and voiceovers a few years ago). Saved me plenty a drive to the studio. AND it's on sale at Buy.com for $55 w/free shipping.
http://www.buy.com/prod/snowball-usb-microphone/203068040.html

Could you be a little more specific about what types of voiceovers you plan on doing? I mean, for most podcasts and YouTube videos and things, and regular ol' dynamic mic (even a USB mic from Rock Band!) will suffice, provided you're recording in a pretty dead space (a furnished basement is great: carpets + drop ceilings = happy sound!). A USB condenser mic like the Snowball will sound better, and a "real" condenser mic hooked up to a preamp will sound even better, but is much more expensive.

But you could buy the most expensive mic on the planet and your voice will still sound like crap if you're recording in the wrong room