if this topic turned into a discussion about developing skills,
Don't worry Rapidshot, that's what the forum is for...
"V" speeds will be an indicated airspeed (IAS), and related to calibrated airspeed (CAS), which is a corrected IAS anyway. TAS and groundspeed do not enter into it, as the V speed is the affect of the actual air on the aircraft. The aircraft does not care about it's groundspeed (until it touches the ground, but even then, it's only the tires), and for the purposes of the affect of air on the airframe, it does not care about it's TAS.
Of course speeds which are limiting, and expressed as "V" speeds (Vne, Va, and Vfe, for example) must not be exceeded. The aircraft is designed so it is easy, while being careful, to not accidentally exceed these speeds.
You're not going to accidentally exceed Vne during controlled flight, unless you're oblivious to the howling sound of the air, and the whining of the engine at near red line RPM, and an unwinding altimeter. If you've buggered up aerobatics, you could - so obviously, aerobatics with a U/S ASI is very foolish.
If you think you're near or above Va, avoid really rough air, and abrupt control movements until you've slowed. When the controls begin to feel more mushy, you're below Va, and safe to do what you have to do.
In a GA aircraft, there is no need to be pushing Vfe, so just make sure you're nice and slow, before extending flaps, and you'll be fine. During certification testing, Vfe will have been established with a reasonable margin to allow for pilot technique.
Because all the "V" speeds are IAS, using the GPS to adhere to them is troublesome. If you're maneuvering the aircraft and getting close to one of these limits, you're probably too busy to be working out the factors between IAS and GPS groundspeed,