Tyre sizes are a pain, there seems to be no consistency, even across the same manufacturer's ranges.
I'm currently running a 2.1 Maxxis Advantage on the back of my 456ti. IMO its not that big a tyre; no bigger than the 2.1 Nevegal on my other bike. I guess it depends on your weight and riding style but I find it too small, so I've just ordered a 2.4 Advantage in the hope it'll fit!
Other Maxxis tyres I'd recommend are the 2.25 Crossmark and 2.25 Ardent, which are both fairly big but not extreme. They should just about fit a 717 rim, but you'll def. get better results with a wider one.
As for road tyres, there are loads to choose from. For commuting the Conti Gatorskins are great – grippy but very hard-wearing and puncture resistant. For quicker riding the Conti Attack/Force tyres are good and not 'too' expensive. I've also read good reviews about Vittoria Rubinos and Michelin Krylions, but not used them.
Hope that helps.