What is the most common things to go wrong with a 2001 Honda Accord V6 Auto>>
Alternators (courtesy of Delphi) sensors, clock lights, wheel bearings and the transmission. As long as it's under 100k miles and 7 years old, Honda will take care of the tranny. Afterwards, they are good about goodwill service... which is usually meeting the customer half-way on the total cost of repairs.
Even though the 6th gens had a known defect in the tranny (bad carrier bearings) not all Accords will suffer tranny failures, so I wouldn't let this deter me from buying one. Forums, web sites, etc. tend to make problems seem worse than they really are.