Cyclamen is one of my favorites. It blooms early in the season and is such a brilliant color it is hard to miss. I also love the delicate pattern on the leaves and the unusual shape of the blooms.
The flowering trees are also a source of great enjoyment. I have a very scraggy wild plum tree which has 2 weeks of glory as it is covered in white petals. We also have flowering redbud and crabapple. The Queen of the Flowering Trees is the dogwood. I have two, a white dogwood and Cherokee Chief which starts out red and fades to pink.