I get this question on a fairly regular basis. My response always is - what do you want to use the printer for? Invariably, the use is printing checks, invoices, etc, etc, etc. My recommendation is always - HP LaserJet. You just can't go wrong with a LaserJet. They work well with GP and supplies are readily available for them.
If you're printing MICR checks, a LaserJet with a standard toner cartridge works well in most cases. The banking industry has moved away from requiring magnetic ink because character recognition software has improved so dramatically. Even so, it would be best to check with your bank to determine if they require magnetic ink, just to be on the safe side.