There are several species and sub-species of maple classified as "Japanese Maples" I would suggest:

1.) Acer shirasawanum 'Autumn Moon' - Yellow, orange, green and red leaves all 3 seasons. Slow growing, and has a nice, layered habit. Everyone goes crazy for this one!

2.) Acer palmatum 'Cindy' - smaller-growing tree with typical layered habit. Deep red leaves, turning to scarlet in the fall. Holds color well even in shade.

3.) Acer palmatum 'Kasagi yama' - unusual brick-red leaves with black veins. Bright red seeds. Color is unique.

4.) Acer palmatum 'Purple Ghost' - similar to Kasagi Yama but has purple leaves with black veins. Brilliant red and orange in the fall.

5.) Acer palmatum 'Suminagashi' - red all year long. Glowing red in fall.

6.) Acer palmatum 'Tsukushigata- - burgundy-red leaves with lime-green seeds.

If you search the forum for these cultivar names you should find some nice pictures which will help you understand what they look like.