While blogging doesn't require a whole lot of extra tools and things to do it - in addition to your browser and either a account at a site for a hosted blog or your own WordPress blog - there are some tools that can be very useful to a blogger.

Graphics or photo editing software
It can be very helpful to have software to either make or modify your own graphics or edit photos. If you can't afford to pay someone you can make your own logo for your blog if you have some graphics software. You may also want to make other graphics to go with certain posts or pages. If you take photos for your blog, you may want to edit parts out for privacy, etc. I have been using Photoshop for a very long time, but I know it is too expensive for many people (I use a really old version!). There are also many inexpensive or free alternatives available.

Pencil and Paper
Using pencil and paper as a tool for blogging may seem silly for something you do on a computer, but actually I find I turn to them quite often. Sometimes if I having a difficult time writing, it is easier to get my ideas out initially on paper and then finish up on my computer. You never know when a good idea might pop in your head when your computer is not nearby either.

I get my best ideas while lying in bed - so keeping a piece of paper and pencil by your bed can be very helpful. I also get good ideas while in the shower - but paper and pencil don't work too well there! I also make sure I bring paper and pencil whenever I leave the house too - when waiting in a doctor's office or walking around in a grocery store I sometimes get good ideas too! And I've learned from past mistakes that if I don't write something down right away I usually forget it!

Dictionary and Thesaurus
A dictionary and thesaurus are really almost necessary tools for blogging. Of course, you don't have to use a printed one - unless you prefer a paper one - but it can be a good idea to keep a dictionary and thesaurus site that you like bookmarked so they are handy when you need them.

HTML editing software
Sometimes you may want to edit a plugin, some other script or even the WordPress theme you are using. There is software available that isn't too expensive and also some free alternatives for editing HTML, PHP, CSS or other code. You can also use Notepad for editing code - but you shouldn't use MSWord - it can add in characters that will mess up your code.

Statistics
At some point you will want to have some way of knowing how many people are visiting your blog, how they found it, who is linking to you, etc. Google Analytics is a great - and free! - service which works pretty well. You may also want to consider a log analysis software to get even more and more accurate information about your blog and visitors.

Feed Reader
If you are reading this and have a blog you probably already use a feedreader - but if you don't you should know that they are a great way to keep track of and read other blogs. I can't imagine how I could keep up with as many blogs as I do if I didn't use one. They are really necessary if you want to keep up with what is happening in the blogosphere, your friends blogs, your competitors, etc.

So - there's a few tools that can be really useful - even necessary for bloggers. Darren Rowse lists more here
and here.

What other tools do you use? Or what would you add to this list?