In praise of primes - which next?

I will agree with the majority who appear to say go for the 21/40/70.  The 50 is too far from the 21 and too close to the 70. The DA40 and DA70 are both good, well behaved lenses across the fiels of view and through a wide range of apertures.  And of course they are all very portable.

I have these lenses as well as a FA50 but it does not get much use, the DA40 does.  I also have a DA15 which gets some use, but not as much as the DA21 as the wider angle is a bit more limiting in its use.  At the other end I have a DFA100 which gets a lot of use both for its extra reach and for its macro capability.

Doug