Help Desk Software?

Can someone tell me the best help desk software that I could implement at my company. We are currently trying HelpStar but I don’t think there is enough functionality in it to properly run our help desk. We aren’t looking for the most expensive package but we aren’t looking to go the cheap route either. We need something that looks decent to the eye and has decent functionality. What do you use at your company? Any that you don’t use that you wish you had? Let me know.
Thanks,
Eddie