Does it mean anything in terms of speed if a distro comes fully loaded sort of speak? I'm talking about heavyweight distros like SuSe, Mandriva, Fedora. Would lightweights like ubuntu and others I can't think of right now run faster because of thier relative small size?

Linux's speed is only affected by what is running at any one time. If you install mandrake with everything and you don't then configure what you want to have running it will go slow. But if you configure it to your needs it can be just as fast(or at least the difference isn't noticeable).

The desktop environment that is used can play a big role in the resources being used. For example, KDE and GNOME are pretty resource intensive. Xfce is a lighter-weight example. (I had a SuSE/Xfce box running very nicely on an old AMD K6-2 400MHz with 256MB RAM.)

Mandrake and SuSE both use KDE by default. FC and Ubuntu both use GNOME by default. You can run pretty much any DE (or at least the few I've mentioned) on any of these, though.

the rpm based distros run like crap no matter how few proccesses are running
I'm not sure exactly why but have some suspicions.

The .deb based distros run ALOT faster but are just as large -- i think debian is actually largest

exactly how the distribution is built and put together and the kernel are the underlying answers i think

I've found PCLinuxOS and Blag to be quite fast, and I use Debian-based distros regularly.

Haha I would hardly consider Ubuntu too be "lightweight". As one poster said about trimming down a Mandrake install, I would tend to disagree. A lot of times the core libraries aren't compiled to be stable / fast, perhaps they are a fairly generic (bloated) compile job. Just cutting out processes and excess software should help a bit, but you won't be touching a true lightweight distro even with a trimmed Mandrake (or SuSE, or whatever). There are core choices made that don't focus on speed, and so heavyweight distros could probably only get trimmed down to "medium weight"
PS: I've found RPM based distros slow too, but then again I'm biased and dislike RPM

I have heard the arguement that rpm based distros run slower than Debian based distros, but its a lot of hogwash. The way you configure your distro and the number and type of programs running at any given time determine the performance of your system amonst other things. I run both Debian Unstable and a lot of RPM based distros and don't really see the difference in performace on the same hardware.

I have also used Mandriva on minimal installations, using fluxbox and it makes a big difference when compared to using it with KDE or GNOME. My point here is that regardless of the size of a distro, you can customise it the way you want and it will work fine.