I have really been debating selling my iMac and going with a MBP + 24" monitor. I have been using a laptop and monitor setup at work and it has been working out fine. Your setup is awesome.
Thanks. In your case you might be better off just looking for a cheap refurb/used notebook since you already have the desktop and it might cost you more to transition but if you don't really mind then by all means go for it. Its a very versatile setup.
In my case the situation was reversed, i already had the notebook and was thinking about getting an iMac to supplement because i missed having a full kb/mouse/display
However, i figured it was cheaper to just get a display rather than buying another full fledged comp. Plus i'm not really a fan of the iMac chin...it'd make the display too tall/high for comfort viewing on my specific desk. Also keeping two computers in sync is NOT an easy task.
Luckily, i found a great deal on the display (shop around or get a refurb. Don't buy RRP...unless you're loaded of course), which made the decision a no brainer for me