I used to use Adobe applications and have found decent alternatives for Photoshop (GIMP), Illustrator (Inkscape), and Premiere Pro (KdenLive) that run on Ubuntu.
Among those, Kdenlive probably measures up the worst to its Adobe counterpart. I am happy with it as an NLE, but I can't deny that Premiere Pro is quite a bit more useable and powerful. The new interfaces do take some getting used to, but they are all excellent tools in their own rights.