Hello there. The Abit KT7A
doeshave RAID. You may or may not use it right away. I have the KT7-RAID myself. Not using the RAID right now, but it's nice to know it's there should I want/need it in the future.
You have narrowed your choice down to two very good boards. Both will allow overclocking in the BIOS (assuming your CPU is unlocked). I wasn't interested in overclocking...for about the first two weeks...now it's getting to be a mild obsession! My current system is also my first self-built system. Once it's up and running and you get filled with a sense of accomplishment and pride at what you've done, you'll probably want to see "just how far" you can take your new "monster" (think Dr. Frankenstein.....IT'S ALIIIIIIVE!) Either board will be good to go.
As far as stability goes, yes, the MSI WAS ranked #1 in stability. With Abit about 1/2 step behind. Remember, the stability tests that Anandtech and other reputable sites use are truly brutal and those test conditions would seldom be replicated in real-world use. I understand though, you want the peace of mind knowing that you've bought the most stable board out there. I've been using mine for over a month. Sometimes I leave it on for a few days, sometimes I turn it off at night. I've added/deleted expansion cards, formatted drives, had about 20 explorer windows open at once, while burning a CD, run loops of 3DMark for about 5 hours. No crashes. Not a single hiccup. Just a mini-testimonial for Abit

Either way, MSI or Abit, you'll be good to go. Major manufacturers' boards these days are very reliable, and the support for the KT133(A) chipset is very mature at this point, so it boils down to what features you want/need. Some boards have bells and whistles, others just bells. Good luck.