Hiya, first post after lurking for a bit
I was in my teens in the 90s so have been lusting after gear for quite a while. My job involves sitting at computers all day, so when I mess around with music I prefer hardware and use DAWs as only as glorified 4 track recorders and to mix & EQ, and I don't use softsynths because I can't sit there clicking and typing for 14+ hours a day any more. Hence me being in to hardware.
I hope it will be useful to dump my thoughts about synths for this genre. Lots of great stuff in this thread, by folks who certainly know their stuff, and I am going to be repeating some of it in an attempt to do quite a wide overview - so apologies in advance for that.
Also please correct me where I have gone wrong!
There is so much hardware out there, I tend to group it by style of synthesis, or application, in an attempt to categorise things. I'll also be keeping it mostly cheap (<300), common & 80s/90s. In rough order of usefulness for DS;
1) ROMplers, Vector Synths, early waveshapers
Very out-of-fashion with techno/electronic folks so cheap as chips. Also quite a few of the modules come with thin & orchestral percussion sounds which are crap for contemporary dance & electronica, but perfect for DS.
Great example of that is the early E-Mu Proteus range - Proteus 1, 2 & 3. Cheap as hell. Also a great source of more orchestral sounds, ensemble sounds... the orchestral ones are DS in a box and can be found for < 100.
Yamaha: SY/TG range. TG are the rackmount/module versions, and as such, they tend to be more expensive than the keyboard counterparts. More pricey are some the earlier 12-bit versions, because of the grainy character -- the TG-33 tends to be most expensive because of this, and the nifty joystick.
Kawai: always overlooked, rackmount versions available. K1, K3, K1r etc. Good workhorse synths for any musician IMO. Can make good controller keyboards too IIRC.
Korg: many. The Wavestation was big. Also DW, EX, M1/3/R, T1/2/3/r, 01/03 up to X1/2/etc. To be honest I would avoid the M1 as was hugely popular, the DW-6000 & DW-8000 were great and tend to be overlooked.
Roland D-range; D10, D50, 110. Also the JV, JW range but that's getting a bit more modern-sounding.
Ensoniq SQ-1 & R, similar architectures to the above.
Peavey DPMs, if you can find them might be worth checking out.
Also if you see a synth by Hohner google it, they rebadged synths by other manufacturers for the european market around this time.
Generally speaking for DS I would go for the earlier versions of all of the above, for their more dirty charms.
2) Related to the above, "General MIDI" boxes
Sound Canvas, Roland MT-32 most famously. Roland MT 100, SC, CM range. These things were designed to play audio for 8-bit etc games and so are perfect for the chiptuney end of things, and not for sound design. andrewwerdna covered these nicely above. Generally for DS, any weird lookin box with the "GENERAL MIDI" logo is likely to be cheap, and a winner.
3) Digital FM Synthesis & friends
Best-known is the Yamaha DX 7. Quite a few in the family - 21, 27, 100. TX are rackmount. The TX81Z is the daddy from that area, if I remember rightly. The FB-01 was a cheaper, half-rack alternative.
Modern cheap digi FM - reface DX or (better IMO) Volca FM. On the release of the Volca FM it sold out and a lot of second hand DX7's started appearing on the market. Volca FM backward-compatible with DX7 patches and more expressive. Not sure why i haven't bought a Volca FM to be honest.
Other manufacturers at the time came up with FM-like synthesis they couldn't call FM, but sounds similar, e.g. Casio iPD synthesis -- Casio CZ & VZ range. CZ's have been flying just under the radar for a looong time, and are loved by techno/electronica types.
Those machines are classic techno machines & proper synths so not as cheap as romplers. Editing their sounds is equally painful, however. On the upside, they are more likely to hold their value.