I did reply to Becky and she was commenting this thing from normal user side, not company stuff as that is quite different world, what works in hobby systems like linux box in corner is not necessarily good for corporate use and vice versa.
However I worked in company at 1998 that used linux servers instead of routers for sharing isdn line, it of course cached transferred data too, so it is very good for certain appliances. HP has been developing own unix/linux version, mac os is again one variant from subject, it is really quite far from being l33t ppl thing. There is already solutions that have embedded linux as OS, it really is not anymore just thing for geeks but coming really into markets.
There is companies that are building linux distros with same kind of resposibility and quality control as windows, maybe even better in some cases.
It would be wrong to say that it is just for geeks, it is however not yet really same level as windows but when I compare 1998 state and todays state, man it is really usable for ppl that even don't like to get hands dirty, nothing like back in 1998 when you really needed to be a geek to get that thing installed.
I know one book keeper that is using linux, she does barely know how to use computer but she chose Linux instead of windows, no problems at all.
Ubuntu is considered one of good distros for beginner, there is also cd image available that you burn to cd-rom and then start your computer from cd-rom so you can test Linux without installing anything, they even send you cd-roms if you ask, free.
It is one interesting future things this Linux.
I'm not saying that linux would be ideal solution and that everyone should jump into it, just I'm trying to say that for some it works really well, it is already usable and not just geek thing, there is companies behind it, lot of.