One of my buddies and I are planning on living in Deer Valley apartments.
I was just down to Columbia this weekend (grew up in Kansas City, but went to college in PA, so not too familiar with Columbia) and looked for apartments. Ashland seemed like it might be nice, but like Tara is on the older side of things. Both those two seem about as close as you can get though.
Katy Place seemed nice enough as did Kelly Ridge, but I ended up deciding on Deer Valley because it was about as new as you can get (I'll be the first person to live in my apartment) and it is nicer than some of the older stuff. 9-ft ceilings were one of the big things for me, I like the more open feel. Price is $600-645 for 2br/1ba and $645-690 for 2br/2ba depending on options (view, 'vaulted' ceiling, etc). You have to be 22 or older to live there, so I don't think undergrads will be two big of a problem and when I went by on Friday night, the place seemed fairly quiet.
In addition to me, my buddy mentioned that he met another soon to be Mizzou M1 who was going to be living there, so it can't be a terrible choice for Med students. It is definitely in biking distance from the school, but also definitely too far to walk. You can check it out at
www.deervalleyapts.com if you are interested.
Also, if you have any questions on Deer Valley or other places, I would be happy to give you opinions on specific places since I am in your same boat and just visited.
Good luck!