I am going to buy an IMac online. Do I order it now and get the free upgrade when Lion is released? Or do I wait so I can have Apple send it to me with a fresh Lion install? Does it matter?
Buy it now. The first release of Lion is likely to be buggy so you can wait a bit after it comes out for these to be ironed out - plus you get it earlier
If you can wait a week or two then I suggest doing that. Life will be easier if you can just plugin your new computer and do your thing instead of spending time....
Normally I would say wait, but as the iMacs have only just been updated, you may as well have fun with it for a few days, the Lion upgrade is painless and very quick (assuming you have a decent connection to D/L the upgrade) and it, in typical Apple fashion, just works.
I am running the GM and it is very nice, boot time is quicker, gestures are awesome (and second nature already, when I go back to my production MacPro and Magic Trackpad, running SL, it seems clunky already !
Chances are if it comes out next week you'd probably need to wait another week or so before all the shop inventory is replaced with native lion installed iMacs. You might as well get it now and upgrade in a few weeks time.
The advantage of buying now is that you will receive BOTH the Snow Leopard AND the Lion OS's (free upgrade to Lion if you wish).
You may find it valuable to have Snow Leopard around, even if you upgrade to Lion shortly afterwards. Particularly if you encounter an app that requires "Rosetta" to run (which Lion doesn't have).
Buy it now. The first release of Lion is likely to be buggy so you can wait a bit after it comes out for these to be ironed out - plus you get it earlier