Here I am again...been working on laptops for years, almost exclusively on HPs.
I could talk all day about all the defective models HP has put out.
I do almost exclusively warranty work. I work on manufacture warranty (as in a year or under), as well as extended warranty units (generally 3 years.)
g7s are still newish, most that come in to me are still under MFR warranty, and the biggest thing that they come in for, as well as the rest of the g series (there's a g4, and a g6) are fan issues.
The original fans tend to seize up and stop working. Which is really odd, considering most of the fans HP uses now a days are magnet based. A little WD40 helps but they still seem to seize back up. I believe it has something to do with the casing of the fan, but I'm honestly not sure. Either way, the replacement fans seem to do really well. I can't say much for if the replacement fans also fail because g7s aren't old enough to be cycling back through in that kind of way.
Either way, g series has fan issues.
Other thing to watch out for, is not a failure of the touchpad or button board for the left/right click, but the covers you push down for the left and right click tend to break in under a year on these. They're held on with the thinnest, tiniest pieces of plastic. They will work but will be loose and get stuck on the casing once they come loose.
I mean, these do sometimes come in for no post issues, but honestly most of what I see are fans. Not that this is a great laptop, but usually each series they put out has design flaws that cause some kind of issue, and that's what they ALL almost come in for. :P