Here's my recent experience with the Wii:
I went to my parents place on Christmas day to see my family/extended family (my mom wanted me to stay overnight on Christmas Eve but the thought of having to be around little kids, and a lot of people, some of them obnoxious, wasn't that appealing, I'm a bachelor who likes my quiet apartment). Anyways one of my nephews got a Wii for Christmas which wasn't set up and my sister asked me if I could set it up for the kids. So I go downstairs to the rec room with it which has a 36" SD tv (the family room has a 42" HD tv but the room was busy unforunately - I wanted to see what it looked like on a HD tv). Anyways I go downstairs, put the sensor bar on top of the tv, plug everything in, sync the wiimote and think I'm finished setting it up.
Then I turn on the Wii and after it updates (it was nice that it picked up the wireless without me having to change any settings) I notice that the Wiimote seems to be "off", basically I have to point the Wiimote higher than I expected. It was extremely annoying and I quickly realize it was because of the tv itself, basically the distance from the top of the picture tube to the top of the tv is higher than the average tv set. I then decide I'll put the sensor bar on the bottom of the tv instead. Unfortunately that's when I ran into the problem of the tv being flush with the edge of the entertainment center so there's no room for the sensor bar there. I then have to crawl behind the tv, clean up a lot of cords, etc, and manage to eventually move the tv back about an inch, just barely enough for the censor.
Anyways after that and changing the setting for the Wiimote to the bottom of the tv it was much better. So I put in Wii Sports and two of my nephews start to play. The first game I select it Wii bowling and they start to play it. Both nephews are 6 years old and I expected them to immediately pick up how to play the game, I mean it's the Wii afterall it's suppose to be easy. Well they both take awhile to figure the bowling out (one even cries which annoys the hell out of me). So things finally start going well and then one of them sits down. When his turn comes around he says the Wiimote won't work anymore. I pick it up from him and quickly realize there's a sweet spot where it works well because of where the sensor bar is and that the couches (one on each side of the tv) are too far to the sides of the tv for the kids to be able to sit on them and play. Anyways I tell them to just stand when they play the Wii because I'm not going to rearrange all the furniture, treadmill, etc, just for the system.
I try Wii Sports myself and get bored of the entire thing in about... umm... 10 minutes, maybe 12. It's not like I don't like casual games, I mean I play Bejeweled 2 and Chain Factor (it's at http://chainfactor.com/index.php try it, it's addictive). Anyways I found myself tiring of the games for the Wii in record time (unfortunately my sister didn't get my nephew Super Mario Galaxy).
I can't say I hate the Wii, just that I don't really care for it. I'm also not as big a fan of the Wiimote that I thought I would be either. Some of the buttons seemed awkward and I (like my nephews) am use to playing games at weird angles sometimes. I mean sometimes I'll lay on the carpet with a pillow, look up and play game like that, other times on the couch, etc, but it looks like it would be more of a hassle with the Wii. Also the vast majority of it's games just don't appeal to me. How could I justify buying a system with only 2 or 3 games I might like when I already have 2 systems (PC and 360) with dozens of games I like and a backlog of games already? The Wii gets a 2 out of 5 from me. Maybe the Wii 2 HD might finally be the system for me (anything can happen)...
