I did it the $$$ way and just bought an Airport Extreme. I now have it set up as my router, with three SSIDs:
1st one: 2.4 GHz and can see the LAN - For stuff like iPhone 4 because it doesn't support 5 GHz.
2nd one: 5 GHz and can see the LAN - For stuff like my MacBook Pro.
3rd one: 2.4 GHz guest network. LAN is invisible to it.
For #1 and #2, they're WPA2 only.
For #3, currently WPA2 but I may set it up as WPA/WPA2, but would only rarely use WPA clients.
yeah trendnet sucks - but it does 450 on 2.4 and 5ghz. you could rock two usb sticks and connect twice to both bands and while it's not load balancing some data would move over each . 450mbps gets about 22.5MB/s versus the 16.5MB/s @ 300mbps.
fwiw i've not found a 5ghz solution that works as good as the 2.4ghz - if you look at most designs these days the 2.4ghz is a SOC (all in one cpu/modem/etc) then they tape on a 5ghz modem - it just doesn't work as good.
For my new Airport Extreme (3x3) in the same room as my (I believe 2x2) MacBook Pro, iperf benches the setup at up to 140 Mbps, although usually more in the 120+ range. That's on 5 GHz. For 2.4 GHz it's considerably slower, up to about 90 Mbps, but usually less.
However, the range is is noticeably better with 2.4 GHz. One floor up and in a far corner, I'm still getting 60+ Mbps with 2.4 GHz. With 5 GHz, I'm getting just 5 Mbps. Ouch.
btw with 300 or 450 you will tear a hole in the bandwidth of anything near you (neighbors) - when i'm running a 300mbps copy of the DVD that router is so powerful that my neighbor complained his wifi was teh suck lol.
I'm not sure the Airport Extreme even supports channel bonding at 2.4 GHz. I currently have the MacBook Pro set to use only 5 GHz (which is supported for channel bonding), but since I'm usually upstairs with it, I'm probably better off sticking with 2.4 GHz.