I would recommend an IBM/Lenovo Thinkpad, but I don't love their gaming performance. The certainly keep cool and last though. My sister has one, since her college assigns all their students one (lucky, right? wait till you see the tuition bills). If a laptop can last one year under her use, without anything going wrong, it'll last for anyone. I don't know about long-term, but she is the person who games on her bed, blocking the exhausts and stressing the fan, yet that Thinkpad keeps soldiering on.
I feel like a lot of laptops are just not well designed for gaming. They're going to have hot cpus, even hotter gpus, so they're almost always big and bulky, to accommodate airflow, and when they're not...trouble can brew. My brother for instance has a Hypersonic laptop. They had good reviews and are respected system integrators, but his ram overheated, the case has warped/cracked overtime from heat, etc...
I know this shouldn't be the case, but consider buying a fan table to put your laptop on, especially if it's on a soft surface, to try to keep it ventilated. Try to keep it on hard surfaces, that's always recommended, but if you can't, try to keep the heat down, don't engage in hard-core gaming.
Myself, I have a MacBook Pro. I still have a pc desktop, and I run Boot Camp and Parallels, so I can always boot up in xp to play games, or run some program in emulation like Windows Live Messenger in Parallels. I run folding@home on it too, running the dual-core at max, so I always keep it on a fan table when on my desk, and when I'm not at my desk, folding is always paused, leaving my laptop cool.
I'm just giving you these tips because it seems the problems you've listed are almost entirely due to heat, because of bad airflow design or use. I hesitate to recommend Dell, because I dislike the size of the standard Inspiron case, yet the bulk of it seems to allow for adequate cooling. HP's rep in laptops is improving rapidly; just make sure you know what you're getting. Don't buy one of their multimedia behemoths weighing 13lb if that's not what you're looking for. They have other designs!
In processors, you're looking for an Intel Core 2 Duo. I would recommend an Intel in the 7000 (7200, 7400, 7600) series of numbers, since they've got the improved 4mb cache, double that of the 5000s. You can save money with an AMD Turion x2, but I really have no experience with them, even though I am an AMD die-hard on the desktop side. (Not to say that I'm not awed by the performance of my work Core 2 Duo 6700, I just can't justify the price difference to myself)
Someone who knows about warranties post more! I have a three year warranty (with extension plan) on my Macbook Pro, I believe Lenovo will warranty you for up to 5 years, if you pay. 3 years next day delivery repairs for them are $119, pretty reasonable.