I was recently pondering the same thing, and I ended up with a Dewalt
DW618 (reconditioned on Amazon it was a great deal - keep an eye on
that page). I have used it quite a bit freehand and currently have it
mounted in a table. I like the low center of gravity and wide, grippy
handles. The depth adjustment is very easy, and the motor slides
easily out of the base. It works with Porter Cable baseplates etc.
There is also a plunge base available, and it comes in a fixed/plunge
kit, but I haven't used it.
I read somewhere that almost all routing can be done withOUT a plunge,
and most of the other times you could be creative and rig a fixed base
to work (by tilting it like a previous poster mentioned, etc.). So
unless you want to start a lot of routing in the middle of a workpiece
(as in making lettering for a sign?), I agree that (on a finite budget)
a fixed-base is the way to go.
Also, good bits make a big difference - a friend has a cheap set ($50
for 50 bits from ebay) and I'm not impressed with those. I've had very
good luck with bits from MLCS (mlcswoodworking.com) - reasonably
priced, free shipping on all orders, and excellent quality IMHO.