I am a little late here.. I have a:
HP touchpad running ICS (Cyanogen 9)
Kindle Fire
ASUS TF300
The touchpad is ok, a bit heavy but ICS is still alpha and the HP WebOS is crap. My kids use it now, it would not recommend.
Kindle Fire, I got one for my wife. I really like it, but I cannot get past the fact that you cannot expand the storage, no camera, it only has 8GB internal storage (free cloud storage for all Amazon's content), and Amazon's app store is limited. You can get one for Amazon Warehouse for ~ $160 US (refurb) but it has the same warranty and support. I think the Nook might be a better choice.
Asus TF300 ($389) A little out of your range but I love it. In fact I also bought the dock ($140) because it is that good

. The screen is bright and sharp (despite the people complaining the it is not an IPS+ display) and it is built well IMO. I am able to connect to my network and stream 720p / 1080p video and it has a micro HDMI out jack which allow me to plug it into a TV. I have been getting ~ 8 -10 hours of battery life, depending on usage. The dock will add an additional 6 hours. All ASUS included apps can be uninstalled and the ICS is basically a stock version (ASUS recently release the source). You can look up the tech specs, but it has definitely exceeded my expectations.