Whatever your reason for not getting the new Apple iPhone 3G, there are plenty of alternatives to it. Most of the major cellular providers have touchscreen phones, but many are not up to par with the standard set by the iPhone and its successor. I hope to help you in your decision for the best iPhone alternative!
LG CU920 VU or LG CU915 VU

Image Source
Carrier: AT&T
Price: CU920 - $399.99; CU915 - $349.99
Best Deal: Amazon.com ($0.01 for either with a 2 year contract agreement)
The LG Vu for AT&T is a very good alternative to the iPhone and my personal favorite. The Vu has a fully-functional touchscreen and many unique features. It is the first phone to be compatible with AT&T's MobileTV (available in select areas only) which allows you to watch some of your favorite TV channels from the comfort of anywhere. It has a decent 2 mega-pixel camera that can also record video. The complaint I hear most often about this phone is its battery life. You get 3 hours of talk time and up to 10 days of standby. Depending on how much you use your phone, you may have to charge the Vu once a day. There are two models of this phone, the CU915 and CU920. The difference between the models is the absence of AT&T's MobileTV on the CU915. So if the service is unavailable in your area, or you don't feel the need for TV on your phone, the CU915 is a cheaper option. The phone also operates on AT&T's 3G network, so you'll get the same fast speeds as the iPhone 3G. All in all, the LG Vu is, in my opinion, the best substitute for the iPhone 3G.
Samsung Instinct

Image Source
Carrier: Sprint/Nextel
Price: $449.99
Best Deal: Sprint.com ($129.99 w/ 2-year agreement)
The Samsung Instinct is exclusive to the Sprint/Nextel network. It features an elegant touchscreen and similar menu style to the iPhone. The Instinct features GPS support from Sprint, which could be very useful. The Instinct boasts a better battery life than the Vu at 5.75 hours of talk time. As with the iPhone, the Instinct features Visual Voicemail, which lets you choose which messages you want to listen to. The Samsung Instinct may be quite the iPhone competitor!
LG Dare

Image Source
Carrier: Verizon
Price: $399.99
Best Deal: Amazon.com ($199.99 with new service plan)
The LG Dare is an exclusive touchscreen phone for the Verizon network. It is very similar to the LG Vu, but has a different menu style and a better camera. The camera is 3.2 mega-pixels, which is pretty high for a cell phone in America. As with the Vu, the camera also doubles as a camcorder. The Dare also has handwriting recognition, which is a nice touch (pun!). It boasts 4.7 hours of talk time and an amazing 15 hours of standby. The Dare is also 3G compatible, as any competitive phone should be. The Dare is a great option if you're tied down to Verizon and would like a phone similar to the iPhone!
I hope that my look into these alternatives to the iPhone 3G were helpful in your search for a great phone! Have a nice day!