Hi there, and welcome to posting on the forums.
If you just need to have basic functionality, go with something cheap. I DO happen to be a keyboard player, and I have 1 actual keyboard and 2 midi controllers.
I have a wonderful Axiom 61-Pro controller, but never use its midi controller functionality - I do it all within Sonar or the synths. I LOVE the action, and its build, HOWEVER it was around $450 or so, and way more money than what I would recommend you buy.
I would actually suggest you take a scroll through Guitar Center's midi controller section.
www.guitarcenter.com and then when you get to the midi controller section, try the M-Audio filter, and you will see a bunch of used and new ones. I DO suggest you look at a 61-note one, but it is up to you. They are cheap and basic functionality, but that is all you need for your limited recording-based data entry needs.
I just took a look through their stuff, and they have used ones from about $80 usd, onon up to new ones $150-$250. I wouldn't suggest spending more than that. I was able to pick up a brand new M-Audio Keystation 88 controller for $129, and love it, but it is basically just to give me 88-notes for when I am triggering grand piano sounds from my computer.
So, anyways - I recommend the M-Audio ones just for basic midi entry. I would not count on them for gig ruggedness, but fine for a guitar player just entering keyboard parts into Sonar.
Bob Bone