I voted "it depends", but usually my answer is "no".
It depends on how fulfilling the experience is, whether I feel like going for the optional rewards, and how much replay I get out of the thing. Basically whether I feel like I went through a grand long adventure when I'm through. An example of a game I felt was too short, once I got good at it, was Wave Race 64. I blasted through the three circuits, didn't feel particularly challenged, and was left wondering "was that it?" Felt similar with Extreme-G, given I unlocked nearly everything in one day. The same could also go for Super Punch-Out, since once you've unlocked all the boxers the only reason to come back is to finish it with no defeats or to down each boxer in the fastest time possible, so it felt like a one-play-worth game.
Beyond Good & Evil felt like a medium-length game, but a tad short since the ending came up sooner than I thought (though granted I knew when I was getting close). Since you can continue to grab the rest of the collectables before finishing the game (er, most of them), I was able to prolong that game's length such that it felt satisfactory. Plus, it was a really good experience anyway, so it felt like a decent length.
Regarding number of hours played, around 40 seems to be the satisfactory "long-ish" limit for me. That's how long I spent with World Driver Championship (and you really start to get sick of replaying the same circuits over and over after a while). I clocked 60 hours with Final Fantasy X, but that felt LONG, that felt more like 120 hours. It was 60 hours of always-changing terrain, never-ending story, and a whole bunch of optional sidequests. I clocked 70 hours with Okami, which is the longest I've spent on a game. Yeah, it felt long, but not nearly as long as Final Fantasy X. Partly because of the numerous sidequests, partly because I left the system on for hours just to listen to the music.
It's well-known that the Half-Life 2 episodes are short. They didn't feel short (especially not Episode 2, given how much ground you cover), so I guess the experience was just that good.
I just recently started replaying HL2 for the achievements. Was that game always long as [dukar]?
Yes. It's what we call "this is the game that makes up for over five years of waiting."
Regarding what WarpRattler said about New Game Plus not feeling that much different from multiple endings... yeah. Because you usually get to go through the game again twice as fast or faster, not just because you know what to do now, but also because you start out with your awesome gear from the last playthrough or experience is doubled. Going through Okami in its New Game Plus mode made me fly through it in under 10 hours, as opposed to 70. It's fun breezing through the game so quickly, but then you lose out on the first experience with its more deliberate pace.
...but screw that, walking on water is always cool.