Hmmm...love questions like this. Not. When put to it, XVI for longsword, or XVII. Single handers being somewhat more difficult. Sooo, for early stuff (9th - 10th) type X's(specifically Geibeg 2's), XII's are obviously well thought of but the blade that gets the props most for 1 handers, XIV's without a doubt. That or XXII's Short and wide. MMM HMM. :D

Since I haven't handled all the different types I might not have the best knowledge to base my opinion on, but I like X's and XIIa's. (I have to admit that some XVIII's are very nice though.)

If I had to pic one? Type X.
X through XII are all good, though.

Type X or Xa for an early period and the types XVa and XVIII for later types ( A really big one like the A & A 15th century

Twohander that seems to have a type XVIII blade profile but doesn't seem to fit any of the XVIIIa XVIIIb etc ... subcategories. )

In any case I like this blade shape no matter what the size of the blade as the best shape for both cut and thrust.

I like the type XII and XIV for a single hander because I like the earlier styles that are primarily cutters but have decent thrusting ability. For a longsword I like the XVIIIa-XVIIIc family for their versatility.

I like a type XIV.W