<Random thoughts about what I know about this>
the better than camera the more drain on your internet connection, and the harder it is to view with remotely because of the bandwidth required to transmit better quality video. Best to keep this in mind when looking, since the camera can't do more than your connection can do.
The linksys wireless ones are about $100, and from what I've seen the quality is decent (friend had one, but doesn't use it anymore) Your not going to see polyps on your sps, but you'll see them on your torch/frogspawn.
DynDns just gives you an external IP so that you can connect. Even if the camera comes with streaming software, you will most likely need this. (I have them for other things, and am happy with the service)
The last time I looked all the "cheap" home security cameras where black and white.. that could have changed though.
</Random thoughts about what I know about this>