The problem with killing a high level wizard is that, by definition, the best ways of killing him are all situational. Good example is one that most people have missed: Most of a wizard's offensive capability requires that teensy tiny little thing known as "Line of Sight", and the rest are incredibly risky to use. A good example of this is a little trick I call "The Hall of Pillars"... lots of pillars, close together, smallish space, but lots of room for a rogue to run around in. AMF scroll would be a good idea, because even with crafted contingency, as noted, there is a fairly good chance they won't work. Not a great chance, but a fair chance, and that's the best you're going to get.

Also in RAW (for 3.5 anyways) is that beautiful little thing called "Spring Attack". I cannot sing its praises highly enough, because it means you can attack in the middle of movement. If your movement is buffed (You would reasonably assume someone attacking a wizard to be at least *somewhat* buffed by magic items and the like), then you're gold. Guerilla style attacks while the poor bugger can't move away, and then can't see you because you're about 5 or 6 pillars away.

Now, for the most part, we've been discussing the highly paranoid wizard who spends several hours in the morning casting all sorts of rollocks on himself before he's ready to face the day. If it's the stay at home wizard, that's cool, but if he's an adventuring wizard, he's not going to have that chance every time. Plus, in 3.5, there is that magic period where if he does cast any spells, he's going to lose out tomorrow. That period is a whole 8 hours. As people have noted, this is essentially a big game of cat and mouse, and 8 hours is a nice time to whittle him down. Most players I know are incredibly cautious with their spellcasting during that time. Let's see, what else do we have scroll wise... oh, yes, there are indeed spells to prevent *any* teleportation, expensive, but well worth it in our "Hall of Pillars" scenario. Any contingency relies upon the spell working, and if you properly prepare the area moments beforehand by making sure they can't teleport away (a basic idea, I would have thought), or, even better, something nasty happens if they try, then you're gold. Lemme just poke through the RAW a bit for more ideas... But any decently levelled rogue will be able to kibble a wizard with casting of, first, some sort of scroll of teleport blocking (I believe there's a really nasty one in the RAW, expensive as all hell to buy as a scroll, but, against a high level wizard, a must), a scroll of AMF (which will deny them most of their abilities), and then kibble them at your leisure... to be honest, after you've teleport locked them, you don't really need anything else in the "Hall of Pillars" scenario, but AMF is nice insurance.