As rick has said at that age you shouldn't need to worry about much. best to go for the 02-03 face lift, before the big nose should be some bargains about. Look in the thread about importing 156's, some mention of nearly new 03 Cars at massive discounts.
Engine wise, the choice is yours,
1.6 Cheap and cheerfull.
1.8 Halfway house, lots about so good value.
2.0JTS good allround performer, reasonably quick, but not mind blowing.
1.9 JTD, wouldn't bother meself....
2.4 JTD, very fast, good economy, bit too heavy for the chassis. Can be remapped to be silly fast.
2.5 V6, rare but beautifull. fast but terrible economy.
Veloce spec is best for handling, but the ride is harsh. It can also be unsettled on fast lumpy roads. The standard set up doesn't work well with the heavier engines, and the bigger wheels.
Optimum for handling is probably a JTS veloce with 16" wheels........bit like mine really
Optimum all round is probably the 2.4JTD....Remapped, and fitted with the HBE Handling kit.