Your ram is fine for any linux apps I'm sure. If you downloaded skype and google earth via synaptic, and you haven't messed with your /etc/apt/sources.list, then you can be sure that they are the correct version, as far as 64 bit and 32 bit goes. My point about the ram is that the 32 bit version of almost any OS is usually more polished. I've run into bugs and config problems in the 64 bit version of ubuntu, that weren't a problem in the 32 bit version, and, wine worked with the 32 bit version, but not the 64 bit version. As I have less than 4 gigs of ram, I really wouldn't see any performance boost from using the 64 bit version anyway, so I went ahead and stuck with the 32 bit version. It's just less hassle.
I've done a bit of googling, and it looks like skype is for 32 bit OS's only right now. They say they plan a 64 bit version "soon", but it's been that way for over a year now. You'll need the 32 bit version of Ubuntu to run skype. Google earth, I'm not sure about. Did you run the install program ? I didn't know google earth was available from synaptic. Did you try downloading it, changing the permissions to "sudo chmod 755" and then "./googleearth" I don't know if google earth has a 64 bit version either, but I think it's just one big file with every version in it, and knowing google, I bet the 64 bit version works fine.
Ahhhh...a bit of googling has also turned up that google earth doesn't have a 64 bit version yet either, though it won't hurt anything to try.
If you want to use these two apps, you are going to need a 32 bit OS. With only a gig of ram, you aren't really giving anything up.
P.S. I don't know much about Ubuntu Ultimate, but newer users of linux have found that linuxmint takes less effort to get set up right, and it's pretty. I use kubuntu myself, but when I install linux for a new user, I usually use linuxmint, because everything, multi-media codecs, proprietary drivers, all just work out of the box, no hassle. Don't download the "light" version. It isn't lighter, it just leaves out things like mp3 support, due to patent concerns. Sort of defeats the whole purpose of linuxmint. Anyway, if you are a little new, I'd try that. Here is a download link. Get the latest version, not the light edition, and you have your choice of default desktops, gnome, kde, xfce, and fluxbox.
Good luck...let us know how it goes...oh...linuxmint is based on ubuntu, so things will seem familiar.