White Flower Farm has some interesting combinations-see the link. I am sure you will get some great suggestions here-lots of creative people on this forum!

Here is a link that might be useful: Combinations

Here's another one

Here is a link that might be useful: Proven Winners

I'm not a good pot tender either. I don't have good scent suggestions, but these all survived my abuse : )
One combo that did well for me was Pink Wave Petunia(the trailing kind) with a Blue Salvia with the silver foliage. Silver foliage is a good drought tolerance indicator. And a short Yellow Snapdragon.
Another one, I still have this one alive inside, is Lemon Grass with apricot gerber daisies, and variegated(white, green, and purple) Sweet Potato Vine.
I've done Verbena that survives abuse. I had some potted with a bushy daisy type flowering annual that I wish I could remember the name because it survived me too!
Maybe someone will know what the daisy type flower was.
I hope you get some other good suggestions too.
Remy

Wow, that proven winners site has some beautiful combos. Had to bookmark that one!

Here's another site with planter combo suggestions--

Here is a link that might be useful: Plant by Number

Last summer I saw huge hanging baskets with huge amounts of brightly colored flowers near the water front in Baltimore where they couldn't have been getting much water. Turns out they were million bells. Just type the name in search on putzers Proven Winner link. They looked like small petunias or pansies and come in a variety of colors. Then I started to see them all over back home during the hottest days of summer with no droopiness, and just bloomin' away.

Million bells have done great for me. They were in sun from early morning until 3pm or so in the afternoon. There are gel things you can add to your potting soil that will help maintain the moisture. I'm going to add them this year to my pots. I've had Victoria Blue salvia in my hanging pots, deck pots and planted in the gardens. They do get large in the gardens, but in the pots they didn't grow as big, which was good. They take all day sun by me, but I am further north than you so I'm not sure about how well they would be in all day sun there. Dusty Millers are another good one for pots in full sun. I don't care for their flowers (I cut them off), but they are good accent plants. White alyssum do well in pots and to me have a nice scent. They need shearing back every so often, but they are great all summer bloomers for me. Certain kinds of coleus do well with all morning sun and can add some beautiful color all season. There are so many different kinds of those.
Good luck!

Kat