After switching to Linux recently at work, it's time for the follow-up post with the tools I currently use for development.
For compiling, I use the standard GCC -- currently 4.3, which has support for OpenMP and is more or less on par with Visual Studio 2005/2008; C++ support is quite good, and I had minimal problems while porting. It's also faster during compiling than VS 2005, which has some weird problems with some generated code I have thrown at it (took 30 minutes to compile a 500 KiB file containing straightforward C code.)
For building, I use CMake, and by now it should be clear that I like it :) I'm really happy so far, especially because it allows me to generate standard makefiles on Linux as well as KDevelop/Eclipse projects. In particular, it is also supported by Qt Creator which can open CMake projects directly. I tried both KDevelop and Eclipse, but Qt Creator really wins hands down at the moment, even though it lacks a bit of polish. Just make sure you use the latest released versions, my Ubuntu came with 1.0 (while 1.2.1 was current), and it's really under rapid development. Supposedly, Eclipse CDT 6.0 also brings a lot of improvements, so I have to give that a try.
Side note on building: I replaced a bunch of batch files with Makefiles, which are really handy for various tasks. Especially as you can build any crap with them, including UIs and documentation without any problem ;)
For profiling and memory checking, you can use the excellent valgrind tool (together with callgrind and kcachegrind). Especially for memory checking, valgrind is probably the best tool you can find, and if there is a good reason to port, then valgrind. It runs the code in a virtual machine, and logs all memory accesses, so you can easily find every memory leak, off-by-one-error and access to uninitialized memory, without having to modify the application.
For UI development I use PyQt. My tools were written using Python anyway, and adding an UI with PyQt was straightforward. You can leverage the Qt Designer to create UIs for it (it comes with a custom compiler), and it's straightforward to integrate. Nokia also provides a LGPL alternative -- PySide -- which might be interesting if you develop commercial applications. For me, the more mature PyQt turned out to be a good choice, didn't have any problems so far.
There's of course a bunch of other tools you need as a developer, and some of these are not exclusive to Linux, but I add them here as well -- some of them might be a good choice to use on Windows, as you can continue to use them on Windows.
For editing, I use Kate and VIM -- VIM is very nice when it comes to large files, as it is very fast even on 500+ MiB sized files. Kate is a simple text editor, nothing fancy, I guess the closest Windows equivalent is Notepad++.
For mail, I use the stock KMail, after trying Thunderbird (which is my primary mail client on Windows). KMail is an integrated part of the KDE desktop, and feature-wise I'd argue that it's on par with Thunderbird, I've yet to find a missing feature.
All my documentation is now written with asciidoc -- a very nice documentation generator written in Python. It requires only minimal markup so the files are still readable as plain text, which is a killer feature compared to docbook and friends.
Well, doing graphics, I also need a 3D app, and in my case I run Maya 8.5. It works nearly without problems (sometimes, the UI shows some weird transparency in the outliner, which might be related to compositing), and I'm simply used to it. Installing on Ubuntu is a bit tricky (you should follow this excellent guide) , but it's possible, including license management from network and mental ray rendering. I gave Blender a shot, but until they start to follow some basic UI guidelines (left-click selects, for instance), I see no point in learning Blender. Don't get me wrong on this, I do believe that Blender is a great tool, but you have to invest a lot of time to learn it, especially if you used other tools (in my case, Maya and MAX) previously. For image editing, I use GIMP.
That's probably the tools which account for 99% of my work time. I hope you find this list useful if you come also try to get started with Linux development, at least I would have saved some time if I knew it beforehand :) What's very nice about nearly all of this tools is that installing them is very easy, as they are free and directly available from the package manager -- something which I miss on Windows.