It really does differ depending on what you're doing. The 3.4Ghz is a lot better for gaming and any single threaded app. So certain programs like Photoshop will appreciate the extra core but if you really want to go dual core I'd wait a bit as it's not really used a whole lot yet and todays offerings will be quickly revised.
What I meant was if they are the same price. I wouldn't pay more for a dual-core, but I would definitely pay the same. Some people would not agree with me and they know more! : )
single core good for gaming duel core good for multithreaded tasks, ie: video editing, encoding etc etc
Once again what are you planning on doing with it? If you're confident and know what you're doing you could always overclock your 3.0GHz dual-core chip (assuming you choose it) and close the gap for single threaded apps. Or you could get the 3.4 and have excellent performance overall and then just upgrade to dual-core when it takes over later on.
