CradlePoint CTR35 Wireless N router
I'm still waffling as to whether the Apple AirPort Express or the CradlePoint CTR35 Wireless N router is more flexible. The CradlePoint is certainly lighter, but AirPort Express is slightly smaller. I typically use this with my Sierra USB 3G/4G modem (Clearwire), but I've also used it as a Wi-Fi client bridge and as a full Wi-Fi router being fed by a hotel Ethernet connection. With an external antenna on the USB modem, I've even had connections way the heck out in the boonies. Since I'm not always allowed to use the electrical outlets (or I'm in the boonies and there aren't any 120V outlets), I've left the wall wart at home and I just run it off my monster battery pack.