$30 for this case? That doesn't seem a little excessive to anyone?
I got my case on ebay for like $9.xx with free shipping. Just search for "droid rubberized case", it looks exactly like the purple one above. Fits well, easy to put on and take off.
The Seidio case is not the purple one (not sure if you thought it was or not), it's the case in the upper left.
Now, if you can't tell any difference in the quality between the case in the upper left, and the purple case and/or the lower case, then it certainly isn't worth an extra $20.
I figure if I spent $200 on what's really a $500 device (Verizon will get the $300 from me over time), I try to keep it in pristine condition. I also like a case that simply feels good in my hands, that detracts as little as possible from the device.
I've tried the Body Glove cases (shown in lower photo), and they were bulky, and certainly didn't ADD anything to the look/feel of my device (a G1, at the time)
The Seidio case has a soft textured finish, comes with some type of soft material on the inside to protect my device, and, bottom line, simply looks GREAT! And... it adds almost nothing to the overall size of the Droid. They are precision engineered to add the absolute minimum in weight and size, while still providing protection.
Twenty bucks more? for me, it's worth it. Not for everyone.