I use Point to Agent. Not going to get into all the details but the photo upload tool is amazing. Especially if you list alot of properties.
The google map and google earth features are big hits with my sellers.
They are fully customizable and you can give each listing its own domain name.
The drip campaigns are great for handling the leads and the IDX will depend on your local rules and regs.
The handshake listings rock. I've gotten several leads off of them already.
The prospect manager for the leads is great.
Listings get sent to google base, oodle and trulia,
you can integrate your blog content into your website to increase natural optimization
The stats and reports are very cool to. I've used these to help get listings and price reductions
anyways I could go on. oh yeah and tech support has been great so far. we bug them often with ideas and they are very receptive.
You can get a free one to try it and build it for as long as you like and when you're ready to launch it and take advantage of the other features then you pay for it.
You can get a free point2 site here
http://agent.point2.com/selfreg/ColdwellBankerJohnstonSelfReg.asp