Yes, Linksys 300N does not go on 5.8Ghz at all, as you said.

Generally speaking, I think that unless you need to buy a WiFi router now, you should wait until the 802.11N is finalized.
I am considering this 300N just because I happen to have one on my desk, unused. Otherwise, I'd stick with G and wait few more months.
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= Taym =
MK2a #040103216 * 100Gb *All/Colors* Radio * 3.0a11 * Hijack = taympeg