I know I'm going to catch hell for saying this but stay away from the all-in-one desktop units. On the surface they appear to have everything you need but in the end you will regret the purchase.
I've had students purchase these (many brands/models) and have never seen one that's actually worth considering. There are many reasons that the computer-based DAW's are so popular. Given the right console/pre's, interface, PC or Mac (I love both!) and software, you can have a very flexible set up that allows you do to much more than a fully-loaded Korg or Roland type rig. Don't get me wrong, these companies do have some great products but they just don't hit the mark when trying to cram everything into one box.
I'm going to catch it on this one too! If you're serious about your music but unsure of your production abilities, spend the money you do have and go to a studio. The money you save up front will cost you greatly in the quality of your final product. I have to say that just because you can afford some cool gear and your buddy knows how to set up your bedroom or basement rig does not mean you will turn out quality from the start. Notice I said from the start? We all start somewhere and need time to learn our craft. I guess this is my personal gripe of guys buying gear, building a website and living the fantasy of being a "Studio Owner" or "Recording Engineer." People like this may pull off impressing someone but the sounds they produce are unlikely to impress you the artist or better yet, your fans. What is more important?
The point I'm trying to make is spend your time and money wisely. If you want a professional product, talk to professional groups and ask them to steer you toward great engineers and great sounding rooms. Affordable, good sounding gear in a crappy room and a green engineer does not add up to a commercial quality release.