Look into cellular (honeycomb) shades in a light color, Will decrease the amount of sun but maintain light and not darken the room during the day. Research if you need the thermal ones. If you plan on being in this house for a long time and can afford he extra for remote controls, definitely consider that option. Its just so easy to control the amount of light and warmth. Otherwise consider the pull down without cords. Safer and less messy. You can always add some kind of built in material covered valance/fabric window topper for decoration if you feel its too boring. Look at companies like home Depot, blinds to go, windowsavers and other companies; they are always having 30%- 50% off sales.

Thank you for your comment. I actually didn't know what you meant by cellular shades, until I saw them, and I said "oh, those!". Anyway that is really a perfect solution, and I did go out and buy them, in white (to match the blind on the living room window), and I installed them today. I chose the blackout version because the excessive sun in the summer is really the main problem, but I'm sure there will be some thermal insulation there in the winter too. For now, I'm happy with the white and simple look. I'll think of valances etc. in the future. Again, thank you for pointing me in this direction!