Now may not be the best time to buy that new iMac because Apple has announced an “event” for Tuesday, August 7th. As usual no definitive word on what exactly what will be unveiled but popular guesses include new Mac designs, the overdue iLife/iWork updates or even updated laptops.

• Think Secret: Apple confirms August 7 Mac event
• MacWorld UK: Apple hosting special event - iMacs?
• MacNN: Apple event to focus on Macs, iLife: Aug 7th

Apple hasn’t significantly updated the case designs for any of their Mac products (other than the iBook to MacBook mutation) since they transitioned to Intel processors. The lower operating temperature of the new chips should allow them to use smaller overall packages then the G5s that were the focus of the current cases designs and with Steve Jobs’ emphasis on functional aesthetics it’s a matter of when not if we’ll see something new. Personally, I would love a compact desktop machine similar in footprint to the old beige G3s.

Rumor sites have been buzzing about an aluminum iMac case design but the mock-ups I’ve seen are uninspired. I’m guessing we might see a brushed or anodized aluminum + black design inspired by the iPhone.

Unless any new iMac can somehow double as a tablet (very doubtful) I don’t expect to see a touchscreen on it. Every ergonomic evaluation I’ve heard about says touchscreens are simply too tiring to use on a vertical surface and a 20″ or larger version of the iPhone’s screen would probably be very expensive. But I also thought Apple would never switch to Intel processors so what do I know.

And if they actually announce a Mac OS X based tablet of any kind the whoop of delight from a certain house in Brigantine will probably be audible to the inhabitants of the International Space Station (yes, I know it’s in a vacuum.)

Feel free to post your guesses in the comments.