MrSavage - 12:18 am on May 29, 2012 (gmt 0)
Regarding IP, not sure if you're consider moving the IP (server) then doing the 301? I personally leave the IP as is and do the 301. Nothing hard and fast I've seen, but shaking up things with an IP in combination with a 301 an entire domain is less ideal or disruptive. Just a personal preference or even superstition. I've done both and nothing was better over the other. My suspicion is that less disruption is best.
In all honesty, provided it's not a complex move, it's very safe in my own experience. If the redirects are complicated then double and triple check everything is in order. I like to get a sitemap from the old domain and then click the links and make sure it's all working as planned.
If I get a better domain I'm not concerned about killing off the good that I had. Tedster mentions a loss in link juice which I know nothing about.
Like anything regarding websites I'm sure there are 100 different opinions on this. Boil down multiple opinions in other words.