For Debian (stretch/sid, x64), I had to install allfonts with winetricks before successfully installing osu!; until that, the installer was unable to find Sans Serif font:
Other than that, everything went smoothly!
Call stack, in case anyone is interested
Unhandled Exception: System.ArgumentException: Font '?' cannot be found.
at System.Drawing.FontFamily.GetGdipGenericSansSerif()
at System.Drawing.FontFamily.get_GenericSansSerif()
at System.Drawing.SystemFonts.get_DefaultFont()
at System.Windows.Forms.Control.get_DefaultFont()
at System.Windows.Forms.Control.GetDefaultFontHandleWrapper()
at System.Windows.Forms.Control.get_FontHandle()
at System.Windows.Forms.ContainerControl.GetFontAutoScaleDimensions()
at System.Windows.Forms.ContainerControl.get_CurrentAutoScaleDimensions()
at System.Windows.Forms.ContainerControl.get_AutoScaleFactor()
at System.Windows.Forms.ContainerControl.PerformAutoScale(Boolean includedBounds, Boolean excludedBounds)
at System.Windows.Forms.ContainerControl.PerformNeededAutoScaleOnLayout()
at System.Windows.Forms.ContainerControl.OnLayout(LayoutEventArgs e)
at System.Windows.Forms.Control.PerformLayout(LayoutEventArgs args)
at System.Windows.Forms.Control.System.Windows.Forms.Layout.IArrangedElement.PerformLayout(IArrangedElement affectedElement, String affectedProperty)
at System.Windows.Forms.ContainerControl.LayoutScalingNeeded()
at System.Windows.Forms.ContainerControl.set_AutoScaleMode(AutoScaleMode value)
at #=qFqELZI4CNHUjKlISqNlqnX2uMei3zPMx8jZ8zLeeBj7Q4x$6KNxWT7M01WdMEh3I..ctor()
at #=qW0tN4ySVT$vmZGnYMncrziuJEtrqKKZPkNtuPZbZmPs=.#=qqFbgVCJT2zxMLRtGCN6VTlroKzNIL3fbyrFSNeSEUw0=()
at #=qW0tN4ySVT$vmZGnYMncrziuJEtrqKKZPkNtuPZbZmPs=..ctor(#=qFEAs5fL7G2eW0XiiKIbOqpMBS0Ah06vQIIelyZcp9_Wd1a4l$n0bUzJBo0EVjKGb #=qG1zuvPrqcHV0WNmt7xC1gvqnBeQl6c5qEFb7wQBQl7g=)
at #=qMJg8u$Xqvw7tXT54izDz5A==.#=qr$P1Dil8E5VEwL$EgqLKZw==()
at #=qeBiB6WYAto2Ihrie8aLoHI0y8Y6oGCnwGtCLe3embDM=.#=qPU2vGuvD17IDXy0rwjzALg==()
Other than that, everything went smoothly!