Thought I'd join up as I've just bought a 2000, X plate 156 2.4 JTD for £1500 a couple of months ago as a "sensible second diesel car for clocking up miles at work in". Auto trader gave me the usual fodder of Astras, Vectras, Fiestas... and then there was my Alfa. Needless to say I didn't hesitate and it got me the 90 miles home from the seller with no problems, and so I was hooked.
I've had to stick a new radiator in it, and I changed the timing belt as well as it was sitting at 127,000 and I've no service history. This aside, it runs wonderfully and goes like stink! I've already fallen in love with it and am looking forward to throwing my work's reasonable mileage allowance at it and getting rid of the wee gremlins here and there (horribly creaky front suspension and steering, warped plastic sill trims, the odd spot of rust, probably a MAF sensor that needs cleaning and a lightly rattly interior)
I might not be able to give much advice to others at this stage, but hope to pass on any of my mechanical experiences if they prove to be useful.