You're gonna find that any band (electronic or otherwise) uses a lot more than one synth. I mean, they may show one keyboard in the video or have one or two on stage (just to make it look like they're playing them), but when it comes down to recording - it's RACKS and RACKS (I've got tonns of hardware synths and need more). And bottom line is - it's the producers that really take care of the band's sound. Even bands like Depeche Mode didn't exactly create their arrangements by them selves. All they did is write music and lyrics and then it was up to a dozen or so people to take it from there.
My point is - if you want to take the whole synth thing seriously and make it more of a career choice and get into recording, TAKE IT ONE STEP AT A TIME!
So far you're on tha right track - You need a multitimbral synth with a lot of polyphony, sequencer (although I'd recommend a computer for that), wide selection of sounds and sonic abilities (If you don't care about knob-tweaking now - you will later).

If you want something for around 1000 bucks here are some good choices:
Roland XP series (XP50 and up)
Yamaha - way too many to mention but here's a few:
SY series, WX series and if you're lucky the EX (although they are normally about 2000$ used. Check out some of their PSRs too (but that's not professional world).
KORG (great for multitimbral stuff - good voice allocation)
Trinity. (lots of FX, great sounds and room for expansion)
and whatever models of a similar design that came out later. ( I'd go whith the Trinrty though)
Trinity (about 1200$ canadian -dirt cheap for what it does!) is very well built and even though the polyphony is only 32 notes (more if you put in different expansions), It works better as a stand alone workstation than any Roland or Yamaha.

There are a lot more other good synths, but for now - check out the ones I've mentioned.
Also let me know if you need synths for professional use or just to play ( Yamaha PSRs are good for that, but I don't know much about them).

You should also visit your local music stores - BEST WAY TO GO.
There will be a lot of help there.
ED