On a busy arty street of gourmet hamburger restos, fashion boutiques and rock bars is a great little art supply store called Curry's.
Inside is cramped, but aren't all Curry's like this? Every single store I've stepped into are stocked to the gills with tons of art supplies but that's good, that means there's a lot of variety.
On each of my visits, I found the staff to be friendly and helpful every time.
The prices are reasonable though I'll admit that I rarely visit other art supply stores looking for a bargain. I come here purely out of convenience and the short walk from my house.
Just a note: This store isn't 100% wheelchair friendly. While the main section of the store is level to the street, there is another level in the back of the store where they sell canvases and paper. There's 4 steps to get up there so for someone who is wheelchair bound, this would be a challenge. But I'm sure that the super friendly staff would offer to help in this situation.