HP are a good brand to go for if you're going to be doing a lot of heavy duty printing (especially if you want b/w laser printers). Epson are good for cheap and cheerful stuff, plus you can pick up unofficial cartridges for about £5 a time. The quality isn't very good in my opinion but you get what you pay for.

I've used Canon printers as well, but only one model. It worked well and held up for several years of good service with three different owners before finally giving up the ghost.