Along Jim's lines about filters...yeah, having two different filter characteristics on hand is VERY useful. My take on the "character" VCF would be to go with a Steiner-Parker Synthacon filter...having had a Synthacon and gotten to appreciate the level of "yowl and shriek" that that design can do, it has always struck me as one of the best choices for a "lead voice" out there. Check Tiptop's Forbidden Planet VCF...probably one of the best versions out now in terms of space (8 hp) and super-simplicity. Another great is Doepfer's MS-20 Sallen-Key version, the A-106-1. Not only is it capable of a lot of different timbral colorations, its resonance path has an INSERT point in it...which allows you to mess with the filter with some non-filter things, like delays, wavefolders, distorters, and the like.

MIDI, though...since you want to use a keyboard controller, you may as well have a MIDI interface that knows what a "class compliant" controller is instead of going thru some other MIDI interface from some other synth, etc. So for that sort of thing, plus expandability (up to 64 assignable CV/gate/trig outs), have a look at Expert Sleepers' FH-2.

Lastly, probably one of the best values in modulation signal screwery has to be Tiptop's MISO. $99 for a tool that can make your mod signals do backflips is 100% worth the price of admission! Either it, or 4ms's SISM...either are ultra-useful.