WOW, you can spend a shit-ton of money detailing some of the larger Mac Pro models...WTF?!

Anywho, I guess my next question is capacity (memory). What kind of space & capability will I really need to ensure smooth transfer of my files? My lil' old Dell here only has the following, and it's over 4 years old, I think:

Intel Pentium 4, 3.20Ghz
1GB of RAM
160GB hard drive

I can't even find anything more specific on this old bird, but that's probably because I don't necessarily know where to find it.

Obviously, anything I get will be an upgrade, and there is no such thing as "the biggest & best" in computers, because this shit is outdated tomorrow. I just want something in the middle-of-the-field that isn't going to cost me an arm & a leg. I mean, I shouldn't need a fucking Mac Pro model as opposed to just the "screen-and-tower-in-one" I-Mac, or should I? Just screwing with customs, for shits & giggles, I built one Mac Pro model over $12,500...insane. Does anyone honestly get what they pay for at this price? Fuck, that's almost comparible to my goddam Yaris!