You're question is a little vague to me. Some quick Googling comes up with things like this, and this. As far as what the best things to have are is really just a matter of preference. However, two things I would say that every web developer needs is a good text editor and Firebug. Firebug is originally a Firefox add-on. They describe themselves as,
It is also available in Safari, Chrome, Opera, and IE6+
I use Notepad++ for coding purpose only, it's by far the less resources consuming and fastest tool. It's free and recognizes a bunch of programming languages.
But if I need to use a tool that has a design mode, with preview and all, I use Microsoft Expression Web. I find it better than Adobe's Dreamweaver, but that's just me, perhaps I didn't hit the limitations of this piece of software yet. This one is not free, it's about $150, but if you use it for a few weeks, it's guaranteed to keep using it afterward. You get a free 30days trial. I use it since the first beta version, now it's currently at the 4.0 version. Never crashed on me, but it can be really slow if you load a 100-page website.