I enjoy turboprop flying, even though MS flight sims to date do not model turboprops as well as piston engined props or jets. Since you specified turboprop-liners, I presume you are interested in those that would commonly be used in short haul and connecting flight service.
Premier Aircraft Design (PAD) offers several that would fit the bill and they are free. PAD's virtual cockpits are generally nice, functional, but are flat panels with 2D style gauges and switches. That often suits me as it makes modifying the gauge layout and avionics package rather simple. The downside is that night lighting of the VC is only through the cabin light, so no back lighting or spot lighting of gauges and switches with an otherwise dark environment.
Bret Henderson's SAAB 340 is really nice and it has a great virtual cockpit, especially considering it's free.
I'm sure Milton's Dash 7 is great, he only does great work, but it's a four engine aircraft and I only fly singles and twins.
There is also a freeware YS-11 out there. I have it, it's nice, but it is complicated and if you don't follow the instructions to the letter you will never get the engines fired.
Another good freeware twin turboprop can be found at CalClassic, the Convair CV580. This is another one that does require following the instructions for start up and flight, but it's not overly complicated. It does have a very nice virtual cockpit with back lighted gauges.
I do have the PMDG Beech 1900C. It is said that the virtual cockpit of their 1900C is better than that of the 1900D. This is a port over from FS9 and it does have some issues in FSX. Nothing that is a show stopper, but one of the biggest complaints is the horizontally stretched GPS display and comm selector switches that don't always want to work in VC. Still, for the price, it's hard to beat.