Internet Explorer - love it or hate it. But there's one thing that you can't do; is ignore it, especially if you're a web developer. A large number of php programmers I know or have interacted with; who know about and use the Web Developer Toolbar on Firefox aren't aware of the Internet Explorer Developer Toolbar. Not that all php developers don't know of Microsoft's offering for Internet Explorer, many developers ridicule Microsoft for bringing it out rather too late, but what they probably don't know is that there's been at least one developer toolbar available for Internet Explorer for 2 years before Microsoft released the Developer Toolbar. DebugBar by French company Core Services has been available for the Internet Explorer since September 2003. Although it is not free to use in a production scenario, I recommend giving it a try.
And if that is a fine start, the one thing where Microsoft disspointed on Internet Explorer 7 was the lack of inline page search. Come to think of it, when you look at the whole focus on instant search in Windows Vista the archaic find dialog of IE 7 just doesn't fit. Unless you are an avid Maxthon fan like me this kind of stuff wouldn't bother you, but those of you who use IE more than they use any other browser, I recommend using either Inline Search by Core Services or Find As You Type which even comes with the souce code if you're interested. The best thing about these plugins is that you don't need to be using IE 7 as they work on IE versions 5+.
Now! If you thought that Firefox 2 has this cool spellcheck feature that has made IE 7 stale, even before it got released, you should check out IESpell.com this plugin has been available for Internet Explorer since 2002. That's right for 4 long years now.
Next up is Bayden IEToys by Bayden Systems which bring a multitude of goodies in one small installation package, it's the equivalent of the Windows xp PowerToys. As it brings to you, dictionary & encyclopedia lookup (of course Wikipedia), HTML source of selected portion (equivalent of the Firefox's View Selection Source) - another goodie for web developers, ImageList to see and copy any/all the images from the current webpage, a highlighter to save you the trouble of highlighting the text after you take your printouts, and this one's my favorite - inspired from Opera: Linkify select any non- anchor or malformed url and rightclick to open it without bothering to copy-paste. It also features Google and MSN contextual search feature which can save you time sometimes 