For Xbox games you need Dual Layer Disks dont skimp on these I would buy Verbs for the best results, I have used Ritek with good results but you cant knock verbs.
Imageburn is a free software which is great for burning ISO game files etc. when you download your xbox game file ISO it will come in 2 files a large one which will be the game and a small one which is called .DVD, The dot DVD file is the one you click on, as this mounts the game file ISO in imageburn with the correct dual layer settings.
Easy enough if you get stuck theres loads of videos on utube.
As for the Wii games just use a external harddrive to play your games off and save your self some money.