Steve Maine writes about my number-one favourite feature of ReSharper:
The other feature I really like is Code Reformatting. Everyone has their own style when it comes to formatting code. For instance, I’m inclined to write void Foo( int bar ), while others on my team write void Foo(int bar). … Since everyone tends to have stylistic instinct that are *just slightly different* than everyone else’s, you can end up with a code base that is formatted inconsistently … Rather than forcing everyone to change their style to conform to a standard, we just configure a default set of Resharper formatting rules and periodically run them on the whole solution. It’s proven to be a big win because it removes distractions, keeps our code looking nice, and doesn’t require anyone to change their own hardwired formatting rules.
This is a great feature and allows everyone on a team to ‘go in peace’ (as Don Box might say). I also really like the configuration dialogue that displays a before and after sample of code to illustrate what impact the setting will have.
Other enjoyable Code Assistance features
The other features I’m really enjoying are the optimize using directives (saving me from having to implement my own) and the Import Popup. Resharper notices what project references are set and if it can't resolve a particular Type it searches the references and if it finds a match offers to add a using statement to the top of the file. Pressing ALT + ENTER adds the using statement without taking the focus away from the the current position in code. Very, very nice.
My only grizzle, and the reason I wont be spending my dosh on a license just yet, are around the auto-completion methods. I'm still finding it a struggle to get the same speed with parameter info as with Visual Studio. I'm also finding the three types of code completion and their associated keyboard shortcuts less intuitive (I'm having to think more) than in Visual Studio (CTRL + space).
Annoying bold Constants font display bug
Finally there seems to be a bug when using constants, and Enums (which I love). Resharper displays them using a bold font but doesn't adjust the caret position - so the cursor is displayed four characters or so past the insertion point - making it impossible to type (a difficult-to-overcome usability problem). Luckily the bold font can be turned off. Under Tools -> Options - Fonts and Colors - there's a 'ReSharper Constant' Display Type. You can then remove the checkbox in the Bold box.
[Update: Scott Hanselman tipped me off that this is a bug - no Steve, it wasn't just you 
- with variable width fonts in Visual Studio 2002/2003 and not a ReSharper issue. Googling turned up this statement of the problem which sounds like it will be fixed in Whidbey. I'd like to apologise to ReSharper, their developers, family members and friends for any distress. I may now shell out my own dosh on this tool.]