First Synth

Any reccomindations for a good beginner synth?  I play piano but have no experience with synthesizers.  My budget is $500-$800. 

Well, I am not in a band currently or anything, and I want something to compose on.

I have the yamaha s08 synth , which costs about a thousand dollars, and I believe is worth the price. For composition, it doesn't have a built in sequencer but it comes with software, and has a good variety of sounds, effects and you are able to play with the sounds which is nice.
anyway, if you have the money I think that's worth it, and if you want something smaller for a synth they have one that is the same but 61 key I think and doesn't have the weighted keys.
Mine I like because it has weighted keys but also a variety of synth features so it's a good compromise between my classical piano side and my prog/rock/experimental/avant garde side.

I would *not* recommend the microKorg; it sounds ok, but the tiny keyboard is awful and there weren't nearly enough knobs or sliders for my taste...

A great starter synth would be the Roland Juno 6 or Juno 106.  You can find one on Ebay or somesuch for under $500; it's great axe to learn basic analog synth functions, plus it's polyphonic so you can play normal keyboard parts if you want.  The 106 is easily programmable, so you can save patches you create.  Alternately, the Roland JP-8000 is a real workhorse...  Digital analog modelling, MIDI compatible, polyphonic, with plenty of knobs and sliders for tweaking.    The JP-8000 can also be had for under $500.

I thought this was about history. I love synths, and I recently had the chance to play (well, goof around) with a real theremin in the "MIM" (Mirador Interactive Museum). Delightfull...