Adding/Moving Exchange Server

I am going to be adding a new NT server to an existing site – and I’m considering making this server the Exchange Server and keeping my old Exchange server as a backup (new server is PIII 600 w/256MB v. old PII 300 w/192MB). This is a small site with about 60 mailboxes. I’ve added a new server and moved mailboxes before so I’m not a complete novice, but can always use more advice! Is it more trouble than it’s worth for the performance gain? How would you go about it? Any gotcha’s you know of to look out for? I’m esp. concerned about rehoming the site, since I’ve had problems with that before. Any advice about maintaining a “backup” Exchange Server – good idea or not? Any favorite helpful TechNet articles?