Update (7/14/11) – It’s looking less like this is happening.
The lastest upgrade for Apple’s operating system OSX Lion is finally hitting the Mac App Store on July 14th.
Lion marks the first time that Apple (or anyone else) is making a paid upgrade available exclusively via online download. This essentially eliminates the problem of large-scale piracy. Unless the upgrade flops like the misguided Final Cut Pro X, Lion should prove a massive cash cow for Apple.
I’m excited because the MacBook Air will receive the refresh treatment sometime shortly following the release of Lion. My first generation Air is starting to drag a bit too much, so I’m planning on upgrading this time around.
(Via TUAW)
The Geek Whisperer 
I might stick with Snow Leopard for awhile, especially on my old MacBook. If I had a new machine, I’d upgrade.
Depending on how much work they put into resource allocation and efficiency, you *might* see a performance boost as a result of Lion… Or it could slow you down.
We shall see.