I have a few thoughts...

First, as others have said, Opera Mobile and browser-switchboard. Can't recommend you a new phone, I'm sticking with N900.

Second, Scud battery for 10-20% more life, or consider external USB power brick with suitable dumb-charger cable (a Tecknet pack and a Proporta cable is a good combination, both on Amazon).

Third, you'll be lucky to find a laptop that can exceed 3-4 hours of web browsing, never mind a phone, but if you really want to then I refer back to the external power packs mentioned above. I carry a 7000mAh pack, pondering a 12000mAh one. Try and run that out in a day...

Finally, rather than replace the phone consider going SIM-only and then adding a MiFi dongle from the likes of 3; this gets you HSPA+ connectivity via permanent portable WiFi (and offloads some of the power requirement of doing so).