...for someone who just has a midi-capable keyboard and some digital
recording computer software?

I'm basically into chord progressions and adding layers of sounds on
top. I'm a beginner in terms of technical abilities, but I know sounds
and I wnat something that sounds professional (not the cheesy keyboard
+ "synth" you find in KMart, unless I'm wrong and you can find quality
keyboard/synth combo machines?).

Looking for something that is basic, easy to use, but still produces
some great sounds. Dont need tons of bells and whistles.

Any insight is much appreciated. Thanks!