[Photogeeks] Fast(ish) macro/short tele lenses for Nikon

After having covered fast short and long zooms and a very fast prime lens, I'm in the market for a prime macro/short telephoto lens.
I've collected two choices:
Nikon Micro 85mm f1.8
and
Sigma 105mm f2.8
The price range is the same (and within my budget) but the former would have the advantage of being faster for low light situations (gigs etc.).

Any suggestions, experiences, tips? Cheers!
(crossposted to a few comms)

Mmmmm

Why is it that a simple meal (marinated lamb chops from the Art of Meat and home-made Colcannon) which cost me less than a fiver, tastes so much better than anything I had last night at the allegedly finest restaurant in Cambridge? The meat was flavourful and cooked to the point and the mash was soft and creamy with lovely bits of savoy cabbage that still had bite.
*sulk*