Its a nice OS but at this stage doesnt have much of particualr note to vloggers, unless you use iChat in which case some of its new features might be useful. Photobooth also records video now, and front row is part of the OS now, although I havent checked to see if any of its podcasting features are improved.
If you use Adobe Premiere or After Effects you probably need to avoid Leopard for a while as I think Adobe need to issue new updates for them to make them compatible. On a fast mac with a clean install Leopard is very nice, and things like Motion 3 seem faster to me. Quickview and coverflow for video files may also be handy for some if you like that sort of thing. But be warned that some features like iChat special effects are disabled by Apple on older Macs, including all PowerPCs I believe, which isnt going down too well. Also it may eat more RAM. So probably not too many reasons to rush to upgrade, and it remains to be seen whether Core Animation will lead to a new breed of sexy apps, as there dont seem to be any apps that use this stuff yet. Cheers Steve Elbows PS. If you have Leopard and an Intel Mac, you might want to check out some iChat/photobooth effects that I butchered together in Quart Composer at the weekend, to try to make up some peoples disappointment that Apple removed some of the effects that were demod ages ago. Others have now joined in and started to offer effects too. Here is the thread, got way more attention than anything else Ive ever said or done lol: http://forums.macrumors.com/showthread.php?t=376295