Your not hardly going to be able to OC at all with any stock fan. IF your buying with the intensions of overclocking i would suggest getting something like a E6550.
I beg to differ with both of those statements.
First, the E4300 doesn't really get that hot. I know that I have a Zalman 9500, but at max load...at 3.1Ghz...I'm only at ~50C load on Orthos, or 45C on Folding@Home (On my E4500). The stock cooler should be able to get you to around 2.7/2.8 (that's when you start needing more Vcore, generally).
Then, about the E6550. The E4300 has a 9X multi, where the E6550 only has a 7X multi. The E6550 probably could overclock more (maybe, to say, 3.5 max), but imagine the motherboard you'd have to have to get there: 500FSB is rarely stable on motherboards, unless you have some golden chip, or give it unhealthy amounts of voltage. However, with the E4300, you don't even have to void your motherboard's warranty to get 3Ghz: 333x9. Given, the max you could do with plenty of voltage is probably not going to be over 3.33. But it is a value overclocking chip. Add that the E4300 is cheaper.
And, maybe a better deal: See if you can pick up an E4500 sometime. At most places, they're the same price (and an 11X multi never hurts), though I got mine for $99.