Personally i would suggest neither.

At it's heart, photoshop is a bitmap editor it's original purpose was for manipulating photos various tools have been added with new versions that make it more useful for web design.

Illustrator is a vector-based app for creating free-drawn illustrations. Again newer versions have added things like pixel snapping to make it okay for web design (but its better suited for logos, visualization etc).

My preference is Fireworks. It's got great exporting tools and I find it a lot faster than working in Photoshop (for web/mobile work).

Remember also that design involves a lot of iteration. If you're concerned with efficiency, please get comfortable expressing your ideas with pen and paper - it's the fastest option :)

Thanks for recommending Fireworks. Seems like the right way to go.

The honest answer is that I dint know what I was doing when I began and Photoshop was the only software I had and I remembered seeing people designing stuff with Photoshop and so I stuck. I still haven't used Illustrator. I ve heard Illustrator is good for creating vector graphics and Photoshop is great for UI design. But please do get a professional opinion.

If you're just starting off I would recommend Fireworks. It's the best of both worlds.

Thanks. I hadn't looked much into Fireworks. But seems like you are right.

I Have decent experience with both and even if illustrator would probably be more fit for the job here , Photoshop is easier to master and can be used in more use cases (like manipulating images)