[Deana]

Meliz, several plants that we like for propogation purposes are vinca, lantana and salvia. They are all inexpensive and grow into sort of bushy/groundcover shape, and they all have abundant flowers (they are small blooms but pretty, abundant and do not need dead-heading). A great climber is Tangerine Trumpet Vine. They climb nicely (you have do some training) and have exceptional color in the spring/early summer. We had a lattice wall of it in our old house and I miss how gorgeous it looks when in full bloom! You may need to check with your nursery/garden center on how well these would do in your climate but they are very hardy plants.
I grew up in Chicago (similar climate to you) and I remember my mom planting something called queen anne's lace - a very pretty white flower that also multiplies. You might also look at impatients or begonias. They grow into a pretty full mass but do require a good amount of dead-heading and some pruning or else they get leggy. I can't grow either flower here - we are too dry and hot.
Good luck - it IS addictive!