The Roland JX-10 is just a gorgeous instrument; it's like the analog synthesizer equivalent of a concert grand in that it just sounds ultra-classy no matter what. It goes for $500-700, and if you want to avoid editing voices with the craptastic "alpha dial" the PG-800 programmer goes for another couple hundred (unless you get a good deal on the pair, as I did,) but it's just an ultra-lush, warm analog sound. Its little brother the JX-8P can be had cheaper, but the JX-10 is basically two 8Ps in a single keyboard, which can be layered or split for some wonderfully complex sounds. There's a rack version of the JX-10, the MKS-70, which has the advantage of a much better MIDI implementation, which allows the use of free computer voice editors in place of the PG-800.
Yes, great synth spoiled by a truly abysmal MIDI implementation. However there is
hope.
BTW +1 for the DW8000. The keyboard can be flakey (the contacts get dirty) but it's got a great sound and is very good value.
The Korg MS-20 Mini ($600) is a modern reproduction of one of Korg's old analog monosynths; its monophonic nature limits its versatility for live performance, but of course in a studio situation you can stack as many tracks as you want - you can even make whole songs with it. It's got a great grungy, organic sound, and its semi-modular nature and direct panel control of every parameter means that it's great for learning how analog synthesis works. Good stuff 
It wouldn't be my first choice. The knobby side is easy but the modular side is confusing and doesn't make much sense. That said, there is a very good series of videos on how to use it though on youtube (look up Automatic Gainsay).
I'm not knocking it as a synth though, it is a fantastic machine. Very unique sound and you can really push it once you get your head around the modular side.
BTW Great track. It shows how versatile it is - I wouldn't have guessed that was an MS-20.
This is a wonderful time to get interested in synths. There's so many available now and some of them are incredibly cheap. The Korg Volcas are an absolute bargain, but there's also the Microbrute and Minibrute, the Bass Station 2, Mopho, Minitaur, Doepfer Dark Energy and many more. Even Roland just announced VA (virtual Analogue) versions of some of their old gear.
For cheap polysynths there're VA synths like the Ultranova, Venom, Microkorg and soon System-1.
Analogue poly synths are more expensive but even they exist, DSI do several and there's also the Analog 4 / Analog keys from Elektron. When I sold the Walker the proceeds went to a DSI Tempest analogue drum machine / synth.
There's also a thriving modular scene especially in Eurorack.
Even the
Amiga gets a mention now and again.