Depends on your budget, the Saitek X52 - google it - is one of the better ones that's relatively cheap. The only thing is lacks is a twist rudder control, but there are buttons on the back of the throttle yoke that suffice more than adequately
Microsoft do some good ones as well that aren't prohibitively expensive
Alternatively, if you really want to spend some cash on some fancy stuff you can buy proper yokes, rudder pedals and engine controls, but they're not cheap.