If you're a prime man, MFT is the wrong place to go looking.
Current primes:
Panny 20/1.7 - excellent lens, fast, sharp (sharpest in center) but with some vignetting wide open (as many other fast primes also have). $399 but coming down.
Oly 17/2.8 - smaller and cheaper than the 20, but slower, softer, and some CA.
Panny Leica 45/2.8 - 1:1 macro lens with OIS, not sharp for a macro lens and too slow for portraiture. At $900, this isn't a lens, this is a blob of ego that refracts light.
Announced/future:
Panny 14/2.5 - pointless lens when the 14mm focal length is covered by
nine zooms between the two manufacturers. 12mm would have made much more sense. Due out in mid 2010.
Panny 8mm fisheye - might be interesting, but very specialised. 2010.
Oly 50mm macro: hopefully as good as their Zuiko D 50/2 macro, and also hopefully faster at focusing. Due 2011.
Oly wide angle prime: probably somewhere between 12 and 14mm. Due 2011.
Oly fisheye: Due 2011.
So it's slim pickings, and a long wait for Oly's lenses. If you're really interested in primes, take a look at the Pentax K-x instead, which is not much bigger than a G body, and whose system has
fourteen primes, most of which are faster than their MFT equivalents.
A lot of enthusiasts (separate from the P&S upgrader crowd, though there is overlap) are using legacy lenses on MFT, but there are drawbacks to that approach. Naturally, there is no AF, and some lenses need to be manually stopped down or manually opened up for focusing. Also, adapted SLR lenses tend to be big (negating the size benefit of MFT) and adapted rangefinder lenses tend to have very long minimum focusing distance. I'm using a SMC-Takumar 50/1.4 lens on an adapter myself, but it's hardly sensible to buy into a system just to fill in the gaps in the lineup with (sometimes non-fully functional) lenses from other systems.
Wishing for more primes here myself. As someone once said, "wish in one hand, sh*t in the other, see which one fills up first".