Mentioning only those on YouTube would have filled the blog's max word limit - eheh, no lah but almost :P
First off, Boyce Avenue. Something like a Rascal Flatt's-kind of band. Love their more mellow songs and their covers as well ^^
There's Grayson Chance. Not bad vocals for a kid. AND he plays the piano too.
And there's Dave Days. He's actually rather good looking although a bit on the thin side (that's a good thing?). Most importantly, he can sing, edit videos and stuff, act and has a funny personality!
And.... Christina Grimmie. I love her voice though I've only heard her when she's dueting with Sam in Nelly's Just a Dream.
There's this band called A Common Year. Actually I've first heard their songs in Nightclub City (Seriously??? ...Yes, seriously :|) Surprisingly, they put up their whole album online for free! I'm not sure how to categorise them but they're a bit on the Simple Plan-, All American Rejects-kind of line.
Last but not, definitely not, least, Sam Tsui and Kurt. They're the best two combos if I've ever seen one (combo) that good! Sam Tsui has awesome vocals and can hit and hold the falsetto rather easily (I think). Kurt is one of the most talented video editor and producer I've ever seen (I've not seen many of this kind of people but still, this counts for something!)
I'm very sure if I hang around YouTube more often. I'll probably find some more singers/ bands that I like. Still, what's with this explosion of new talents huh? I can hardly keep up with the best songs now lol =)
Anyhow, good luck in building yourselves music careers! You guys and gals can make it! I'll wait eagerly for your upcoming official albums and music videos. ;P