Switching your base technology, and some pitfalls to avoid.
When you search for a very specific piece of information you don’t yet know, and your own damned site is the first that pops up in the results, you will groan.
When you check the link because you can’t resist and actually find the very answer you’re looking for on your own damned site, you will groan louder.
PHP is a snap, except when it isn’t. See for example the recommended reading list every fourth refresh or so. What. Ever.
OS X use continues to be joyful. Building a PHP-driven site one weekend on a Mac, which was formerly an ASP-driven site on a PC makes one feel gleefully subversive.
.htaccess files are a must. If you don’t have them, move to a server that will let you. Do it, and don’t look back.
Using an old Movable Type installation to generate an .htaccess file when completely re-mapping your URL archiving scheme is genius, and very necessary.
MySQL is probably great, and wonderful, and hoorah. Don’t try to build a MySQL-driven site in a single day when you haven’t yet learned a thing about it.
Don’t ever try to move a Movable Type install without first exporting all your entries through the interface and saving your templates. Trust me: never.
Hosting your site on a static IP will save your life one day. Do this.
If you switch hosts, don’t stop paying the former until you are sure everything is moved over to the latter. Burning bridges is not advised.
Even if your broken links are only temporary, provide pages explaining why or you will spend more time responding to e-mail telling you that you have broken your links than you will fixing those links that you broke.
Most importantly: when you are extremely busy and your server goes AWOL and you just don’t have the time to fix it properly, remember that it’s not Armageddon and people will forgive you for a few days of not reading fresh content. They will. They’re good people.