Has anyone tried Steam on Ubuntu?

Enable 3d Acceleration in VirtualBox config

Here runs fine with Ubuntu (Wubi Installation)

Did you enable 3D acceleration on your virtual machine's display setting , like this?
Edit: Also, don't forget to install Virtual Box Guest Additions.

Mine is Wubi with Nvidia Optimus. Working perfectly with primusrun

A friend of mine is successfully runnin it

I downloaded Ubuntu a while ago to get the Tux on TF2. I didn't even manage to download Steam...

You should use a lighter desktop/window manager, like xfce.
Of course I'm not sure what games you will be able to play in a virtual machine anyway, or more importantly why are you trying to run steam linux in windows.

The only suggestion I have is make sure the latest version of Guest Additions is installed on the Ubuntu machine.

You need a processor with VT-d for 3D acceleration for work in an VM. You can find VT-d in some nonK processor (3570+3770), Xeon, and 2011 i7s. If you really want steam on Linux, just run a native installation of Linux.

Works fine using the Ubuntu from Wubi installation.

Steam need to do a lot of improvements on the Linux version, with or without virtual machine, sucks on both

have been playing for a month now ... dual boot with win7 on separate disc ... tried it trough VM first but it's much better this way

Yes, but installing AMD driver was quite insane, I try it few times by myself and it always screw ubuntu but I managed it with help from steam linux community so head that direction when you need help link. I don't use virtual box I have it installed with live cd and it's good OS once you learn how to use Terminal there is always something to do.

Ubuntu seemed like bloatware to me, but yeah, Steam worked fine on (another way) dual boot Ubuntu (also Wubi install).

Much to my disgruntlement, I wasn't able to get Steam to run when most programs would in Linux. Missed out on the Tux TF2 item even though I had been using Ubuntu for years before. :(

I had no problems running it on a wubi install, but I can't help you with VirtualBox.

worked totally fine for me, but i'm dual-booting. i've used virtualbox in the past and it doesn't support 3d graphics, so if you want that you'll have to run ubuntu in something that doesn't remove the ability to use 3d graphics.