First I recommend you check if your hardware is Windows Vista compatible. This will let you know if you need to spend more money on hardware upgrades even if you computer is new. Go to the link below for the "Windows Vista Upgrade Advisor" this will tell you if your hardware is compatible with vista and let you if you should upgrade or not. http://www.microsoft.com/canada/windows/products/windowsvista/buyorupgrade/upgradeadvisor.mspx
My opinion on windows vista as of presently, is to wait let them work out most of the bugs! I would give it at lest 6 months. Like any new operating system they are know to have bugs in the beginning. Only after testing from customers are the bugs found and fixes released. For example SP1 and SP2 for windows XP. Hope this helps?