I am on the same boat and looking forward to the release of the 3G version of this case. Currently using the Belkin Silicone Sleeve. The Defender may look funny to some, but for my needs and intended use it really fits the bill!
I absolutley swear by my Otterbox Defender for the first iPhone. It's the best case I've ever known, and I've owned probably all of the well known cases for the iPhone v1, except for any Vaja cases.
It looks like, right now, that the new 3G iPhone Defender case will come in three different colors. It will be in Black on Black, Black on Yellow, and White on White. Also, we are trying to have it available by the beginning of September, but that time could change depending on production. Please email me if you have any other questions or concerns.