External Mic for Acoustic Recordings

[mrchainsaw5757]

So for now i have just been using the built in mic from my MBP. I can make it sound decent, but i really want good quality without spending a ton of money. So i was looking into buying an external mic like a USB mic. I have my eye on three of these, any thoughts?

http://store.apple.com/1-800-MY-APPLE/WebObjects/AppleStore.woa/wa/RSLID?find=snowball

http://www.samsontech.com/products/productpage.cfm?prodID=1810

http://www.micflex.net/