> My network card doesn't work well with 802.11N in some configurations, but
> is rock solid under 802.11G.

> Did you ever figure out which chipset you have? Once you get a terminal
> open, run this command
>
> lspci -v | grep -i net -A 8

I just went through this excercise, so I'll post my 2 cents.  I have
no idea if this is relevant, but it may be helpful.

I have a new-ish Core i3 laptop with a Realtek wired connection and a
Ralink wireless card.  I couldn't get the wireless working in Debian
Wheezy.  I installed Wheezy from a jigdo ISO so I knew it was the
latest kernel, etc.

I finally fixed the issue this morning.  Steps I took:

Connected via wired connection
Added contrib and non-free to my sources.list (required files are
non-free binaries)
apt-get update
apt-get install firmware-ralink
apt-get install firmware-realtek

I don't know if it was required, but I went to /lib/firmware and set
all the files to permission 664.  I read a blog post about someone who
had an issue because the files weren't the correct permissions.  I
figured it couldn't hurt.

Those commands re-write the initrd, so I figured it was best to reboot.
After a reboot, with wired connection unplugged, I was able to connect
to wireless.

Brian