Felon said:
So, I'm going to dive into an 8th-level character that actually preps his spells. Sure, I've run more than my share as a DM, but this is first time playing one, and that has its only ittle nuances, and requires its own gear too. What should a wizard (in particular) be spending his money on? How do I alleviate the various hassles associated with spellbook management and security? With the group I'm in, I might even have to worry about my spellbook being damaged by player actions.
First, ask your DM if he would be willing to reduce the core costs of scribing spells. 100 gp/page will consume an awful lot of money if you intend to assemble a wide variety of spells. (I suggest asking for 10 gp/page.) Likely he'll say no, but you're no worse off for having tried.
How many hassles you run into with spellbook security is going to be very group dependent. Some DMs may make it an occasional issue, others may not consider it at all. I would suggest a back-up spellbook, but if it never really becomes an issue then that's an awful lot of money flushed down the drain.
Overall, I suggest specializing. That extra top-tier spell per day goes a long way to improving your endurance. Don't give up Conjuration, Transmutation, or Abjuration.
Magic item wise, you want a Headband of Intellect and some good defensive items. Beyond that, scribe scolls whenever you get the chance. If you fancy being a crafter, wizards are excellent at it. Get Craft Wonderous Item and possibly Craft Wand.
One underestimated resource is spell research. It takes a week per spell level and a 1000 gp per week. If you have the time, researching a specific spell for a specific task offers some interesting opportunities.
Generally, I like to leave at least one spell slot of each level 'open' at the beginning of the day. It's a rare adventure when you can't pause for 15 minutes to more accurately adjust your spell load for the needs of the day.