Well regarding the maintenence needed to be done at that milage:
The water pump seems to fail quite a bit on the audis, whther it be the 2.8 30v, 2.7, or the 4.2. Usually the waterpump will fail before the timing belt does. My indie mechanic has seen em go as early as 40k when he was working at the dealer. The labor to do the timing belt and the water pump are the same, so get em done at the same time.
The cam adjuster seals. They have been the same design for so long in audi engiens, and are known to leak oil. This only takes a few more minutes when doing the timing belt.
Transmission fluid is NOT lifetime. Maybe lifetime of the transmission; but you'd defiantely want the fluid chaged by 60k miles. You will likely have to go to an independant mechanic for the tranny, many dealers stick with the "lifetime-it-never-needs-to-be-changed" additude; if dealer does do it, the charge $300 and up for this service. Indie is about $200-$250.
Front control arms. They tend to fail. I just got done replacing all 8 front control arms and all four shocks on my father's 1998 A6 2.8 30v (yes, its a FWD). Shocks were about $380 for all four, and the control arms were $600. I did the labor myself, indie mechanic will charge about $350. Also the tie-rod ends fail prematurely, those are about $100 for the pair.
Fuel gauge sender. Famous for erratic reading. Part is about $75 for non-quattro, about $150+ for quattro (the quattro has three sensors, the FWD only uses one). Labor is about $80-$100 at an indie.
Front window guide motor clips. Sometimes the plastic guides break, and this doesn't allow the window to go up or down. Parts is about $40 and labor is about $80 for both sides, so about $125 total for the front windows.
The center information gauge cluter display also is know to fade (the design like this is used on many cars and the same thing happens to them, they begin to faade after use, its really a desing flaw). It isn't really that big of a problem as the car will still function even if it fails; it's just an info diaply. If you want it chaged, part is $500 and up. Labor is like $100.
Brake fluid every two years. Oil change every 7.5k-10k miles with a good synthetic like Mobil 1 0w40.
thats about all I can think of right now. I do alot of the work on my dad's A6, cept for things like the timing belt and tranny fluid. If you have any questions, don't hesitate to ask.