I recommend the triangular reflectors if you plan on getting one. I bought one last year and it's been a revelation - you can hold it one-handed with a camera in the other, and if somebody else is holding it it allows them to see what they're doing, unlike a round reflector where you often block your own view while holding it two-handed. I have a Lastolite one and it's spectacular, but there are much more affordable knock-offs on Amazon.
Overall, though, I highly recommend a good on-camera speedlight with some sort of nice diffuser or bounce card. I don't really believe in on-camera softboxes, but you can get some awesome results with the indirect bounce-type ones. I like the Gary Fong ones because they go on the flash head sideways, which allows you keep them upright when the camera is vertical, which means you don't have to deal with a flash bracket.
Even in brightly-lit places like AX's lobby, a flash can be a great help since the sun is coming from overhead and the background is very bright. It lets you get the balance between the subject and background right, and if you use the flash for fill, you've suddenly got a pretty nice "studio" lighting setup with the sun coming through the glass and acting as a giant softbox main light, and then the on-camera flash as a fill light. The fill light is also critical when shooting outside under that midday July L.A. sun.