I stopped playing at about 50 hours.

Total, I have played 170 hours, though 130 of that is with my first character. I don't want to mess things up with my third one, so I am going real slow.

I'm actually having trouble with playing more aswell... but I'm only at a total of 50 hours
The main save is at 26 hours, level 30, with all the best guns, 123 locations discovered... and I don't know what to do.
NV failed at one very important thing, that Fallout 3 got perfect: The locations.
The locations in NV are all just dull and boring, unlike Fallout 3. Most are only buildings or caverns with nothing remotely interesting in them, and others are just a waste of space!(Wrecked Highwayman!)
Furthermore, the ones that actually seem like they could have an interesting back story(Hell's Motel), contain nothing.
Exploring has become boring in NV, because I know I can expect the same things over and over again, and nothing ever changes... Sad to say so, but despite the size of NV, there's not really too much to it... :sadvaultboy:

I've spent well over 300 hours on Fallout 3 (12 characters) and around 100 on Fallout: New Vegas.

Looking at how long some others have played, I feel like the baby lol (1st play through - 62hrs, 2nd - 21hrs). But I have 168hrs and 38hrs and all the achievements on 3 though .

Back to Oblivion, waiting for 'the patch'.

Have an F3 character at around 1000 hours, though...

I finished my 4th play through yesterday. Now completed all 4 endings and have about 260 hours clocked up. Now I'm taking a break before I get burned out. Will play again when the DLCs appear.

Blah.. It must be like with the other games

Oblivion:
First playthrough: With the "oooh and aaah" first impression I got like 23 hours, then got fed with the crap leveling system
3 years later: around 100 hours, with mods. Lotsa mods. Until I had to re-format mah hard-drive! <_<

Fallout 3: about 40 hours. Finished it in 40 hours I say!
Week later: about 66 hours. Then lost my interest. That game svcks so much for an evil character. I want to be evil, not http://tvtropes.org/pmwiki/pmwiki.php/Main/StupidEvil!
Year later: 120 hours. With lot of mods and DLCs to get that bad taste out of my mouth.

NV: Still playing it, I am somewhere at....140 hours I think? I even managed to skip mah school few times. :facepalm:
Restarted my playthrough numerous times, but hell it's still fun for me. Can't say the same about unmodded Fallout 3. :sleep2:

I played FO3 for like 700 hours total (I have issues). Right now I have like 200 on New Vegas.