get the 23, dig up an old crt from under a pile of junk somewhere and get the best of both worlds.
I'm usually a fan of having 1 main screen, however I've found that having a second screen of any sort is quite handy for various things. I use my old 17" flat crt from 2000 as a second monitor and it has worked out great. I like having the whole screen dedicated to what I'm working on (photoshop or lightroom for example), but i also like to have itunes or a quicktime audio window for the stern show or this american life etc., plus i can have a finder window of the files i'm working with over in the little screen, or a video, a web browser, gameday live if there's a sox game, etc etc etc. Expose is great, as are virtual desktops, but i prefer moving my eyes to the side a bit instead of activating expose and searching for the right window. For a while I even used a 15" ibm monitor from about 1997 for the job, it looked lousy but who cares when it's just a finder window or itunes.
it also allows me to watch a video on one screen while my girlfriend works on the other.
if the ugly old beige crt bothers you aesthetically, you can always wrap it in aluminum foil, then run a stiff paint brush over it, i'm sure it'll look just like an apple.