Welcome to the wonderful world of Linux.
Ubuntu is one of the best Distro's if you are new to Linux but as was said here, OpeneSUSE is also good and you can have a look at Mint as well (Mint is a version of Ubuntu with most of the bells and whistles pre-installed.)
As in that article there are some things you should always install to get the best out of the system.
There are many ways you can run Linux. In a Virtual Box, though that wont let it run at it's full potential. I swopped them around, running Ubuntu on my work laptop and XP in the Virtual Machine.
You can also Dual Boot and there are a lot of options regarding this. On my Home PC I have partitioned the drive into 3 parts. The 1st 80GB I loaded XP on for Games. The second 200GB I designated as a bare drive for My Documents and the last 40GB I installed Ubuntu. So when my PC boots up, I can pick Windows to play games or Ubuntu to do everything else with the partition in the middle being shared between the two OS's so both can see My Documents.
Do note that you can play some games on Ubuntu with Wine like Half-Life 2 but some won't play along hence why I was forced to keep an XP partition in case.
Another important thing to note is that you do not have the same 32bit vs 64bit problem that you have with other OS's. ALL Ubuntu packages come in 32bit and 64bit so there is no real reason to install 32bit anymore. And with 64bit you are able to see more than 3.2GB of RAM.
Lastly a great package for monitoring Bandwidth usage is with "vnstat"
Open the terminal and type:
*sudo apt-get install vnstat
*enter your password and when it is installed type:
*vnstat -u -i ppp0
*replace the ppp0 above with whatever your adapter name is. To check, type "ifconfig" and it will list all your network adapters. "eth" means ethernet, "ppp" is modems. 3G modems typically show up as ppp.
* then at anytime, type "vnstat -m" to see your monthly usage.
Top noob tip I can give you, remember that Linux is Case Sensitive. Commands, Foldernames, Filenames, none of those will work if you do not type them in exactly as they should be.
Kind Regards
David