+1 for the Tamron 90mm f2.8 - great value, razor sharp, good weight and to be honest I love it
You can extend its macro ability with extension tubes as well.
The only downside IMHO is focus hunting at times (low contrast situations mainly) - that's what the focus limiter is for (keeps it either in the macro range or the normal range).
However, to be fair you'll find very few complaints about prime macro lenses of any flavour. BTW I got mine from the marketplace here.
+1 for Metz 48 as well - I've got one (from Adorama) and it works a treat with the Tammy as well. The tilt & swivel head is very useful (the Pentax 360 doesn't have that). Its only downsides IMHO are the cryptic menus and its inability to be a master controller.
Good luck with the choices.
Cheers