Greetings and answers:
The Linksys routers are not Gigabyte 108 compatable and never will. Cisco decided to not use the Atheros chipset inside and therefore uses a channel muxing type of approach to achieve higher speeds. This is called Speedbooster. Tom's hardware guilde a long time ago had an article comparing the differences between Atheros and Speedbooster. I'd suggest looking for it. The biggest problem with Speedbooster is that it is not based on any standard (not that Atheros is either, but at least more than one vendor uses it).
Point: If you want to be able to use your 108 capabilites get either a Netgear router or a D-link router. Either one should work (at least their 108 models should). Stay away from their 108 802.11a models that are out now.
**Important note: You will have to configure the routers properly for 108 to work. Also, people have noted that even though their connection in their taskbar says 54Mbps, they are in fact getting 108 because windows can't see the 2nd channel. The Atheros works by broadcasting on TWO channels simultaneously. This causes problems in a few cases and needs attention.
1) If you are in a crowded wireless area, nearby people will not be pleased by you overlapping their channel's broadcast.
2) More channels means more chances of interference. If you have lots of wireless phones and other devices in your house/residence already, finding one unoccupied channel can be hard...much less two unoccupied channels.
3)108 is a lie. Just like 802.11g (54Mbps), you only get 40% or so of total throughput. After taking interference, distance, signal strength, overhead, etc. into account, you might get close to 45 to 60 Mbps actual bandwidth. 802.11g is anywhere between 25 and 35 total, and Atheros is two of these.
4)The channels must be setup correctly in the settings. I'm more familiar with the Netgear ones here. 108 operates in three modes:
a) Off - duh, its one 54Mbps channel or in 802.11b speeds depending
b) Compatability mode - allows backwards compatability for 802.11g devices only. Every so many seconds its drops back to g speeds to let them talk on the network. It should be noted that this mode is not really a mode to let the g device talk but to let your 108 devices talk. Even though your connection says 108 on your end, it is really 54 (so that the rest of your older devices can talk too).
c) Full 108 - your 54 or 11 devices will not work or see the network.
**Adendum #2: The compatability mode for 108 is not exactly as I stated it. It does operate in 108 mode most of the time, but it drops down for miliseconds to see if there are any g devices it can hear. If it hears one, the whole network drops to 54 until that device is no longer on the network.