I'm not going to offer any advice for which ones to choose but I'd recommend thinking about at least a couple of things before going on a spending spree.
First, are there going to be other plants nearby that you would want to coordinate the colors with? If no, then pick any color that you like. If yes, try to pick plants that will give you color combinations you like.
Second, how big is the bed? Would you have room for a row of tall daylilies in the back and short ones in front? Would you only want ones with large flowers (over 5") so that they can be more easily seen? Make sure you check scape height and flower size before ordering.
Third, do you want the bed to have flowers for an extended period of time? If so, choose cultivars that bloom early, early-mid, midseason, mid-late and late. If you choose all midseason bloomers (with no rebloom) your bed will look spectacular but only for a relatively short period of time.
Fourth, do you want/have time to deadhead. Many people don't like the look of the faded flowers (especially when the neighbors can see them) and spend a lot of time taking off the spent flowers either that evening or the next morning. They also want to encourage more blooming by not having pods set on the plants. Think about whether or not you'll have time to do this on a daily basis. Some plants look awful with spent blooms because they can hang on opening buds & prevent them from opening properly. Other cultivars form lots of bee pods which you may not want.
Definitely check out any daylily farms in your area. Nothing beats getting freshly dug clumps that you can transplant right away. You can also see how well some colors hold up in your climate as some reds and purples look great first thing in the morning but awful later in the day if they are in full sun.
I'm sure there are things that I'm forgetting but if you plan you bed carefully you'll have an amazing display!
