I'd like to give a BIG BUMP for MORE MIDI LOVE in Reaper!!
There's not a lot of options for midi composers on the Windows side of the world. Cubase is very good in most ways. Sonar's midi is pretty good, but needs updating and improvement. The others have left me wanting in midi or other areas.
Here are the midi features important to me -
1) First class piano roll ( just take the best of Cubase, Sonar, and Fruityloops
that shouldn't be a problem 
)
2) An event inspector. Click on a midi note or clip and it tells you everything about it- start time, end time, note name/pitch, velocity, etc., etc. Plus you can edit any of these parameters directly in the inspector.
3) Groove Quantize (for both midi AND audio). Oh man, this is huge for me.
As I said in another Justin, I really appreciate what your doing with Reaper and how you communicate with your customers and potencial customers!