1) "messing around" with the FSB won't harm the computer, so to speak, but it won't give you an overclock either by itself. You can't simply raise the FSB and expect your system to be stable. Won't happen, otherwise everyone in the world would do it. It's not that simple. And even IF you were successful, your overclock would be so minimal that it wouldn't even be worth your time you spend just going into your BISOS to make the change.
2) Tens of thousands (or more) people over the years have proven beyond a shadow of a doubt that raising your voltages slightly will not wreck a computer. If you absolutely CRANK IT UP, then your computer should just crash and you reboot at stock settings. No harm, no foul
3) I can appreciate your hesitancy to raise voltages, I truly can. But you've come here for advice, and there are COUNTLESS experts that have been doing this for years. If you don't want the advice you get from everyone, that's your prerogative, but then don't complain about it either. Generally speaking, everyone here is very helpful and also constructive about any criticism.....and we all do it for free because we want to help. We're not getting PAID. So if you don't want to listen to advice and facts, that's fine, but then just exit quietly.
So, to recap:
-if you want to overclock anything of consequence, you will need to touch the voltages
-otherwise, juset buy a C2D chip, some cheap RAM, and leave it at stock....it will still be a FAST system
-ASUS P5B-Deluxe is a good motherboard. If you don't want it, don't get it. Pick something else. MSI is a good choice, and so is Abit Pro. We'll give you the BEST mobo choice, but it's your call. All of those motherboards are fine, so just get the cheapest one since you won't be doing real overclocking. Just get a cheap 945 chipset mobo, some cheap RAM, save yourself the money and hassle, and then you get a decent system and everyone's happy. If, however you decide to do some REAL (and proper) overclocking, then the P5B-Deluxe is great. So is the MSI, so is the Gigabyte, so is the Biostar, so is the P5N-E, so is the EVGA 680i. You need to give us a complete list (or website link) for what's available, or else we can't help you.
So, you need to face the facts. Help us help you.