Question : best tools for front end development HTML,CSS, JavaScript, cross browser compatibility, W3C compliance

I would like to know what tools do you recommend for front end web development/debugging?

I.e. HTML,CSS, JavaScript, cross browser compatibility, W3C compliance, front end web development

The main ones I use are:
- Firebug
- IE Tab (for cross browser compatibility)
- IE Web developer toolbar
- Firefox Web developer toolbar
- Bobby (for checking W3C compliance)
- W3C's own HTML and CSS validators

Any others?

Answer : best tools for front end development HTML,CSS, JavaScript, cross browser compatibility, W3C compliance

That is about all that I use.  I would also add YSlow or the Google Page Speed Analyzer for FireFox.  They help you identify slow loading components.  Also, http://www.websiteoptimization.com/services/analyze/ can be used to help you identify how many objects are being loaded, what can be consolidated, etc.