Looks like you might like to contribute to this project or a similar one.

I personally use AdBlock and FlashBlock on my N800 given I have to pay for the Kb and in general I rather not pay to see ads.

Personally, I haven't thought much of the default search in MicroB, but I guess you can hack your own HTML file for the homepage and put whatever search engine you see fit.

As per other browsers I have Midori and Fennec installed.