ilovefuzz.com

I 2nd the recommendation of DSI Mopho or used Evolver, plus a MIDI Keyboard. Both have built in sequencers plus audio inputs, so they make nice effects boxes as well. Evolver has analog and digital oscillators, the Mopho has sub oscillators, both have feedback

For MIDI keyboards, a used M-Audio Oxygen 8 would be a good option, or something similar with a few knobs.

I have a Mono Evolver Keyboard. It can sound amazing, but it can be difficult and time consuming to get it there. With the desktop version, expect a steep learning curve. If you put the effort into it, it can be very rewarding, but I'm not sure I'd recommend it as a first synth. On the other hand, it comes loaded with 512 very good and useable presets if that's your thing.

http://www.vintagesynth.com/

The Synthfinder here is quite helpful, though a little outdated.

Thanks guys. Like I really need synth GAS right now. Some cool units in here!

I wanted to say thank you sooo much for the Shruthi-1 advice 2012 "year of the Shruthi-1"

Can't go wrong with a microkorg or alesis Micron!