I receive all of these subscritions, hopefully this will help:
PC Gamer- Used to really like it, now layout sucks and reads kinda crappy. More emphasis on flash and game previews, not enough on games themselves and very little on hardware anymore.
Maximum PC- Just signed up, excellent mag (sister of PC Gamer). Much more emphasis on technology and hardware
PC World/PC Mag-Kinda for n00bs or people who want to think they know a lot but really don't. Not bad for comparison shopping but they love crappy brands like Acer and Emachine, and that generic Fry Computer brand. Also, as Beed said, lots of emphasis on applications rather than raw hardware and games. Individual components are rarely looked up, it's always prebuilt stuff.
Computer Gaming World-Great gaming magazine, my dad turned me on to it after he quit getting PC Gamer. Basically what PC Gamer should be imo. Lots of great articles/reviews/news. Not as many exclusives as PCG tho, that's why I get them both still.