Windows application(s) Linux equivalent(s)
Adobe Photoshop GIMP
Adobe Illustrator Inkscape
AeroFly
FMS
CRRCSim
ElStEr Taxbird
foobar2000 Rhythmbox
MPD with pympd
Google Earth Marble (or try their WinE-Version)
IrfanView GQview
Microsoft Office OpenOffice.org
Miranda Pidgin
Nero Nero Linux
Picasa F-Spot (or try their WinE-Version)
PopTray mail-notification
PortableApps
U3
PorTools
l-portable
Klik
Putty CM + PuTTY grcm or ~/.ssh/config
StarMoney Moneyplex (or try their WinE-Version)
Total Commander Gnome Commander
Tux Commander

See also: