Hawaii Five-0 had a couple of things going for it right off the bat. First, James Marsters (Spike from Buffy) appeared on screen within the first 3 minutes, so right there I was excited. Second, there were lots of explosions and gun-play in the first 5 minutes, which again, was hitting all my buttons. And third, Scott Caan is really funny.
As some of you may remember, Hawaii Five-0 began as a cheesy cop show in the 1980s with Jack Lord. Now it's a serious minded cop show in the 2010s. The pilot was slick, well-written, and interesting, but I think it was a bit too serious. I'm hoping the show is able to break out of the "CBS procedural" mode of shows that are too impressed with their own cleverness, and just make it fun. They're cops! In Hawaii! And they catch bad guys! Keep the good writing and quick pace (and the explosions and shooting), but don't take yourself too seriously, guys. Right now, Scott Caan is kind of the only light part and it seems like they could do better.
I definitely plan to keep tuning in, and I've heard they are setting more of an overall arc to the show, which sounds promising. The last thing CBS needs is another CSI, NCIS, Criminal Minds, blah blah blah, and from what I've seen so far, Hawaii Five-0 seems to be breaking out of the pack. So give it a try!