@Breefield While TextMate and to a (much) lesser extent TextWrangler do have features that make them very handy, they are not analogous to Coda. The idea behind Coda is to unite the armada of applications web developers use all the time into one window. No more switching between a text editor, the terminal, your web browser, and reference material, you can access them all from one application conveniently.
Right now the only competition for Coda, at least directly, is Espresso. As of right now, Espresso is 1.0, but it still pales in comparison to Coda. Most of the features haven’t made their way into the app, and many of those that have are boorish at best. The app shows a lot of promise and if CSSEdit is any indication, Espresso will mature very well and give Coda a run for its money.