[dagw]

If you like the basic 'fantasy' setting of D&D, but want a game with a more gritty and 'low' fantasy feel I very can highly recommend trying to find a copy of Warhammer Fantasy Roleplaying.

If you want a game which is more realistic and almost entirely 'straight' historic medieval Europe, but where magic, as they believed in it at the time, is real, go check out Ars Magica. Ars Magica is especially recommended if you like playing mages and want a game with one of the most fleshed out and 'realistic' magic system ever seen in a role playing game.