I'd rather not see any reboots. If it was terrible the first time I don't want to try to see a bad show improved. If it was a good show the first time they're not going to make it better. If anything, they'd tarnish my fond memories of it.
The funny thing is that every now and then I'll see re-runs of a series that I loved as a kid. I'll set the DVR to record the series, and when I hit the play button I wonder, "Were we really that desperate for something to watch on tv back then?"
As a kid, The Dukes of Hazzard was the best show ever made. Now I can't stomach it. Same with Gomer Pyle, Gilligan's Island, Mary Tyler Moore, Happy Days. I can't fathom how I liked thirtysomething at all, much less liking it as much as I did back then. It's godawfulhorrible.
And some shows start out great and quickly get terrible. The early MASHes were good, then the show ran out of good ideas and it turned to M*U*S*H. Someone mentioned Tour of Duty. I have the DVD set, paid a fortune for it...the first season was fantastic, but then they kind of turned it into a soap opera and it faded. It really had a lot of potential and there was so much more they could have injected into it.
As for the Hawaii-Five O reboot, I thought they did a great job with the casting. A great job with the humor and chemistry between Steve and Danny. Where they came up short is with the plots. At least make them semi-realistic.