Yes.. I'd add the ability to know when you don't know enough. Most designers come to lists and start asking questions on stuff they know nothing about but need to know asap because their client is expecting what they have requested. Some designers are not upfront with the client on this respect, and can end up costing the client time because they are still struggling to learn something new to them. The best thing to do is to pass the job on or to contract out for the aspects of the job you can't do. I would find this problamatic as my fees would not match the price to be paid for these jobs from the overal budget. Far better to pass the job on... I think one designer should be doing the whole job then it all fits together nicely. The exception might be graphical work as you really do need a talent in that respect when it comes to cutting edge.
We all approach things in a different way.. half the stuff I read that other designers do with their clients I'm either in awe or shaking my head about how ethical they are being.
I find it extremly flustrating that clients are paying designers vast sums sometimes .... heck would you go buy a washing machine without checking out all the brands? Or a new car on performances and if it fits your needs? Why do some clients just accept whatever the designer tells them? Frankly your getting what your diligence pays you.
Unless you work half in and half out of code at the very least. Can validate a template, understand what CSS, SEO, Accessbility and Usebility mean ... start small and work up. Join lists and forums and ask questions and never stop asking questions. Try to find a mentor who can steer you in the right direction. Try to have goals throughout the year so you can look back and know that you know so much more than last year.
Tina