Linux
=====
It is highly suggested to MD5SUM your ISO before burning a coaster to do this in Linux / Ultimate Edition it is simple supposing in this example you have downloaded it to your desktop using UE 2.6 32 bit ISO open a terminal Applications >> Accessories >> Terminal and enter the following:

cd Desktop
md5sum ultimate-edition-2.6-x86.iso

it should return the following:
cf9e2d59c8921c49f0d7b9e8972061dd  ultimate-edition-2.6-x86.iso

If the hexdecimal number is anything different you have a corrupt download and should download it again, sorry.  See below chart for other O/S's.

Once you have verified your ISO is good... Burning an ISO in linux open K3b Applications >> Sound & Video >> K3b:

Select more actions at the bottom select burn image and select the ISO you just downloaded.  IMPORTANT!!!  Select the slowest burn speed your drive is capable of burning, this ensures you burn a good copy.

Windows:

Grab a MD5sum tool for windows:
http://www.md5summer.org/

Browse to the folder you downloaded the ISO and hit Verify sums once again please see chart below.

Burning:
Use your favorite burning tool be sure to select burn image and burn at your drives slowest speed.

Enjoy Ultimate Edition,

TheeMahn
MD5SUM                            Release
=====================================================================
dfed949027ff6c1702f3736e8ad2f2b6  ultimate-edition-2.3-gamers-x86.iso
7d3cd6f46af7c66ed7e4df1657bc5ea5  ultimate-edition-2.6-x64.iso
cf9e2d59c8921c49f0d7b9e8972061dd  ultimate-edition-2.6-x86.iso
26c4ff8e0249e662f5dc86bc16d937e4  ultimate-edition-2.6-gamers-x86.iso
9a382b7c8c112e1894634fbbb4582fec  ultimate-edition-2.6-gamers-x64.iso
0b82382322790c27a43f3d8815f09001  ultimate-edition-2.7-x86.iso
fd5f2b0724ebb2507625383e702e7b90  ultimate-edition-2.7-x64.iso