I just finished a long post iContact for your blog, especially business blogs. I used the Flock browser for preparing that post and there is no Google toolbar for that browser. I very much prefer to use the built-in Spell-check in the Google toolbar for preparing my posts, and I will explain why later.
Reason why I use Flock for preparing that post rather than my preferred FireFox with the Google toolbar: I have more than 1 Blogger account, and that means more than 1 Google account. Nothing sinister about that. When Blogger Beta was first introduced, there were lots of complaints in the Google Blogger Help group - not being able to see their previous in the Dashboard and thus not being able to access them to create or edit posts, etc. I didn't migrate my account then to the beta account, but stared a new Blogger Beta account to test the new features, and started Testing Blogger Beta (now New Blogger), which I still update plus create new blogs (I am afraid of running into Blogger limits). Further, I have other blogs for other purposes like my environmental blogs such as Enviroman which require a different profile. And I do multi-tasking and thus often have more than 1 browser opened in my computer simultaneously.
Anyway, as promised, I will now explain why I prefer to use the built-in spell checker in the FireFox Google toolbar. As mentioned earlier, when I prepared the long post mentioned above, I had to use the Flock browser which don't have a Google toolbar. I was forced to use the spell checker in the Blogger post editor toolbar. That is OK as long as the words that are misspelled has an alternative presented to you is included in the list of alternatives presented to you when you proceed to correct the mistake. But there were a number of spelling mistakes in that long post, for which the correct spelling wasn't listed in the list of alternatives. I had to click "Resume editing" and the vertical scroll bar didn't remain where it was but scrolled automatically back to the top of the post editor window. I had to spend a lot of time searching for that misspelled word which was extremely irritating. If I had used the built-in spell checker in the FireFox Google toolbar, there will be other alternatives - Edit, Ignore all, Add to dictionary. I would be able to click "Edit" and correct the spelling there and then (without having to go to the trouble of having the click "Resume edit" and wasting my time searching for that misspelled word which wouldn't be highlighted when using Blogger spell check) and then immediately proceed with checking the rest of the post of misspelled words. If those are "words" used by Blogger for the HTML for images, etc., I can chose to add them to the dictionary. Or I can chose ignore and continue with the editing or preparing.
There are other advantages about having the FireFox Google toolbar which I like, including the PageRank bar which you can use to check the PageRank of your blog or any other sites easily. There will be privacy issues involved but I am not concerned as I don't think I have anything to hide. There is also another post explaining why having the PageRank bar is useful at Precautions to take before linking to a site (click BACK button to get back to this page).
I also like the built-in Google search box in the Google toolbar:
As you can see, you can chose to search only the site you are on (which will be very useful if you are searching for something in that site, but the site creator didn't provide for a site search box) and other options.
One more thing is the ability to toggle highlighting of search terms in a page which can help you zero in onto something you are searching for in a page: