I am building a new gaming computer for my daughter and me.  We like to play the Red alert, age of empires and the RTS LOTR games.  Will we be able to play these games on Vista 64 or do i need to install Vista 32 or do I have to use XP i would rather use vista 64 but most important thing is that the games all work.

those particular games that you mention (especially Red alert) need special requirements just to run properly in WinXP(compatibility etc) if i were you i would stick with XP and not downgrade to vista.

LOTRBFME2 works with Vista fine. Here's a list of older RTS I've played on Vista (32 and 64) without issue.
 
Warcraft 2 & 3
Star Craft
Age of Empires II
Empire Earth
Age of Mythology
 
Also I've yet to run into a game that works on XP that absolutly won't work on Vista, and have played many windows 98 titles on Vista.

Pcnut,
 
I gave the Red Alert demo a try. I hadn't realised how old it was! well it installed but I couldn't get it to play since the patch would not apply to the demo. Every thing case off without a hitch until the patch trys to patch the RA95.exe and it won't since it's not the full app. However it's supposed to work with the full game on Vista.