on the other hand - he's quite a big name at the moment and would bring in the crowds (of Dr Who nerds)

Yer but the thing is that I love him as the Doctor same with the person who plays Jack in Torchwood. I will always think of them as the Doctor and Jack from Doctor Who. Its hard to think of them in somthing else. I don't think David Tennent could pull Moist off well.

"You know why big brothers where born first? It was so they could protect the little brothers and sisters who come after them." Ichigo, Bleach Episode 3.

Were he still alive, I would gone for Jeremy Brett (the best Sherlock Holmes) but as it is, I think Alan Rickman would be perfect in the role of Vetinari.

For me it's got to be Alan Rickman as Vetinari - he just suits it perfectly and is a damn good actor too!

Saw a clip on YouTube of Jeremy Irons and absolutely hated it - how could he give him a speech impediment? That's just not Vetinari at all!
Also saw a clip of Charles Dance - difficult to tell with such a short clip but one thing which was screaming out at me was the fact his hair was his usual ginger. Vetinari's hair should always be black.

I love the suggestion of Philip Glenister as Vimes, I've never been able to decide on anyone who would suit that role until now but I reckon it could work.

I agree Alan Rickman would suit it well, or Richard E Grant would do a good job in the role too.
Wasn't keen on Charles Dance