Well I've been looking to hook up a 21" monitor to my MB. I have the correct cables, but I'm wondering if its worthwhile to hook everything up. What I'm really worried about is if my MacBook is going to run very hot and make the fans run more than ~3500 rpm. What I'm looking to do on the external monitor is just browse forums, maybe some video but I doubt it. My specs are: 2.1 Ghz 4GB Ram Is it worth hooking everything up?