Hi Rich
I've had the pleasure of owning a 2.0TS as a company car years ago and now privately owning a 3.0 Super. Vivian's answered the keys question, here's what I think:
Trim: I'd go for the Lusso, because you get leather. Now I know leather seats aren't everyone's taste, but I had the base 2.0 and it had fabric seats. They just seem to get dirtier, are more difficult to keep clean and you'll never get tired of the leather smell! Treat the seats with somelike like "liquid leather" and it'll always stay good looking and good smelling!
5/6 speed - I think all 2.0's were 6 speed after late 2002. I remember looking at one in the dealers when my 2.0 was being serviced, around that time. Base trim but had a 6 speed. Mine was a 5 speed, but the 3.0's are all 6 speed manual and I would say that extra cog is worth it.
My 2.0 never let me down in any way, shape or form, but it did suffer from a few niggles - I think this is just part and parcel of being an Alfa! I'd make sure all the electrics work, check the central locking doesn't stick on 1 of the doors (common), check the oil level - if it's low then it may not have been looked after. My 2.0 used to drink oil (not a leak as it never left a tell-tale puddle on the drive) but as long as I kept it topped up it was fine. Take it for a good test drive, accelerate hard - make sure it's smooth and linear, stick it in a high gear and accelerate from a slow speed, check for big ends knocking. Drive slowly at full lock - listen for clonking. If any of these happen, best to walk away as it will be expensive. With my 3.0, I had a mad rush to the head and bought the first one I saw, even though I had doubts about the test drive. £2K of new wheels and servicing later she's fine, but for the £5K in total that cost with the cost of the car, I could have got one a few years younger, so be prepared to walk away if in ANY doubt - there will be others to look at, despite them being an uncommon sight. Mine had 60K on it when it went back (thanks to the government's new taxation laws at the time!) so I can thoroughly recommend the 2.0. To be honest - it's more nimble through the corners as well. The 3.0 makes a fabulous noise, but it weighs about as much as a liner so it noses on really badly in corners and chews up bushes in the suspension. The 2.0 still makes a great noise (don't all Alfa's??

) but it is a much better bet in the corners. I used to get between 32-35 MPG on my daily commute into work, so not too shabby on the fuel either, considering the size!
AND - how many do you see on the roads? Exactly! It's nice to be individual an different rather than Mr Mondeo or Mr Passat.
Good luck with the hunt - when you find one please post a pic!