Is There a Place for 802.11a?

Computerworld - I hear it all the time: "802.11g gives you the same throughput as 802.11a, so there is no reason to upgrade to 11a hardware." But that statement doesn't take into account a fundamental advantage of 802.11a: radio frequency diversity.
The concept of RF diversity is a simple one. You take a contentious resource, like the RF spectrum in your office, and divide it among several different users to ensure that everyone gets his fair share. This is something we do all the time in data networks with technologies such as quality of service and virtual LANs. While these technologies will eventually make it to the wireless world, you can start separating your networks now by using different radio technologies for different applications.
In the U.S., the 802.11b/g radio spectrum occupies part of the unregulated 2.4-GHz industrial, scientific and measurement band. This set of radio frequencies is used by many other products and protocols, including cordless telephones, baby monitors, walkie-talkies, microwave ovens and Bluetooth. The fact that the 2.4-GHz band is unregulated gives you the ability to install your 802.11b/g hardware wherever you like, but it also means that anyone else can install his own 2.4-GHz band product wherever he likes.
As more and more equipment is added to the same RF band, it becomes overcrowded, and overcrowding of the RF spectrum can lead to degraded performance for wireless equipment. This performance degradation can manifest itself in many ways, but it's usually through lower throughput and shorter-than-expected range.
The 802.11a radio band is in a 5-GHz unregulated section of the RF spectrum, much like the 802.11b/g band. The advantage, however, is that 5-GHz technology isn't as ubiquitous on the market as the 2.4-GHz band. While there are more devices available to run at 5 GHz today than there were a few years ago, it's still not nearly as saturated as the 2.4-GHz band. So there is a better chance of finding a quiet piece of 5-GHz band to operate in, as opposed to 2.4 GHz.
In both 802.11b/g and 802.11a, the RF spectrum is divided into a logical group of channels. Adjacent channels overlap slightly, so it's best to use channels that are far enough apart to ensure that they don't interfere with one another. There are three such channels in the 2.4-GHz band and 12 in the 5-GHz band -- eight for indoor use and four for outdoor use.
So, which do you pick for your installation? I would say both.
Currently, most laptops that ship with an 802.11 option