i use a big ass hp 2600 colour laser jet thing. i think it's a 2600 anyway. it does great flat colour, but printers (as in place down the road) are so cheap these days i would never get letterheads and such done in house. i don't quite get how this digital short run stuff works, but you can get colour printing done these days for a fraction of what it used to cost.
i got a cmyk invite done on a3 250gsm board for about £25 for 50 copies the other day...