Yes, certainly you can mix and match on a non planted tank, and go with whatever color combo you find most pleasing.
Diodes on a roll as you described are not appropriate for growing plants, either. By virtue of a lack of heat sink and cooling available, those kinds of LEDs are usually in the 0.3-0.5 watt per diode range, which are not powerful enough to grow most types of live plants in a tank as deep as an 80. You would need to be in the 3W per diode range to provide proper lighting for plants. Unfortunately, LED
lighting for planted tanks is still fairly newer technology, and appropriately powered fixtures are quite expensive - usually on the order of 2 to 3 times as much as equivalent T5HO fixtures. They do have advantages though - namely much less power draw (you electric bill is lower) and they do not require bulb replacement (they last for 10+ years of normal use, where as T5HO bulbs need to be replaced every 6-12 months for optimum performance, and good t5ho bulbs are not cheap).