Kyocera makes very good printers and the toner is much cheaper than anything you can get for HP. Even their smaller models' toner tank lasts around 7000 pages. If you need duplex, take a look at the FS-1020D, 20 ppm, duplex, very robust, postscript 3 and pcl 6 support. The FS-920 is slightly slower (18 ppm and doesn't offer duplex).
If you want it cheaper, the FS-720 is 100 € less than the 920, but doesn't offer postscript or pcl.
No matter what brand you end up buying, make sure the printer has postscript and pcl. This way, you can be sure you can use it for a long, long time (as in years). Most can spit out around 14-20 pages per minute (A4), so they'll be plenty fast.