It is all I use, so I would not know what to compare it to. The handful of times I had to work on Office 2010 I was pulling out my hair. Nothing was structured, menus all over the place and it took me longer to format the document than actually writing it!
As an ex-WordPerfect user, OpenOffice's (now LibreOffice after the fork) layout makes much more sense than Office. The one app where I miss some functionality is Impress (Powerpoint replacement), but it's nothing major.
I love Thunderbird since I do not need the advanced features like calander and whatnot Outlook provides. I find it very customizable and it just works for me, it does the job, a email client fullstop. There are other more elaborate clients in Linux but I'm not able to comment on them since it has been years since I last tried Evolution, Kmail and the likes.
Unfortunately I can't comment on Thunderbird, but for me Evolution does the job beautifully.
I use GIMP and after following a few online tutorials (I have no graphics designing background) I find it very, very powerful. There are other apps as well, but I keep going back to GIMP. I know it is not PhotoShop, but last time I checked you can use PhotoShop filters in GIMP?
Agreed. For the kind of graphics editing I do, GIMP is powerful enough (the only feature I miss from Photoshop is macros, unless I'm stupid and just haven't figured it out yet).
Try and stay away from WINE and only use it for the most essential programs that you MUST have. It will save you time and effort to rather find a native solution that works for you.
Yeah, Wine can be very hit-and-miss.
Ubuntu is probably never going to be Windows, but if you sit with it long enough and you're willing to sit back and think about a problem when you encounter it, it's a very secure, fast OS. I installed Linux on my PC a few times in the past, but always went back to Windows because, to be honest, I wanted quick fixes. When I finally found a version I liked and got it working just the way I expect it to (10.04), I stuck with it. Installed 13.04 yesterday and haven't encountered any problems yet.
A must-have app if you want to keep Unity is Unity Tweak Tool. It's available in the Software Centre.