Ya if sideloading apps is the main stopper you're pretty much hooped there. You can do this with jailbroken aps (the iPhone simply uses debain apt, so you can imagine installing normal *nix things and jailbreak apps are very easy, just apt-get install) but the normal app store apps are pretty much appstore or appsync only (though appsync is close to sideloading, can install apps from itunes or from safari directly).
While you DO need to jailbreak to get the good stuff, I still think the iDevices are more geek friendly once jailbroken. The combination of apt, full bash, openssh, full gnu tools, and a massive support base really make it a pleasure to use (again, once jailbroken).