Id say a good place to start would be the new Ultimate Spider-Man series. Its only on issue 3, its a very good read and its a brand new character so you'd know as much as everyone else already. While im mentioning the Ultimate Marvel Universe, try and pick up The Ultimates Vol.1 as its just an excellent book and would probably sell you on the entire Ultimate U.
As for normal Marvel U, id say you could either wait for the Fear Itself event to end and we could tell you what books seem to have good jumping on points or try reading Avengers #1 and New Avengers #1 as theyre only about 17 issues in so far from their relaunch.