Trackpads and wi-fi has been working for me for a long time(not implying this isn't a problem for many people), but what drives me completely insane is the video cards. If you are planning to run linux, seriously re-consider buying laptops with hybrid graphics. The graphic card might or might not run, the card switching will most likely not work, but you can ignore it since you can work with the intel card, right? Well, no. Most of the AGP, whether used or not, will eat up power, the fan will run at full speed and your laptop's behind will be hot enough to stir fry some veggies.
If you have a laptop with hybrid graphics, and you can't make it work, just switch off your discrete card.
https://help.ubuntu.com/community/HybridGraphics
Laptops in general, and linux laptops tend to run hot. However, don't mess with power settings a lot. Putting harddisks on powersaving mode(refer hdparm) so that they become idle puts unnecessary strain on the disk. You can try out experimenting with cpu frequency(cpufreq-set).