I don't know that much about lights, so I'll try to give all the necessary info...

20 gallon high with guppies and a bristlenose pleco, several healthy red crypts and needleleaf ludwigia, plus I'd like to get something floating in the near future but haven't had much luck with Anacharis lately (but want to try some from a different store), no CO2, occasional undergravel fertilizer tablets (Seachem FlourishTabs).

So as of yesterday, my lighting was one 22" Glo Power-Glo 24W T5 HO and one 22" Coralife F14-T5-BP 6700K (I only know what some of this means, I'm just quoting from the bulbs). This morning I awoke to find that the Coralife bulb has apparently burned out, so I just wanted to get some opinions as to whether I should replace it with the same thing or with some different bulb. Obviously I would like my fish to look as nice as possible and my plants to be as healthy as possible, but I have no interest in pursuing CO2 or spending a lot of money on a bulb right now.

Thanks for any advice/opinions!

You have a T5HO fixture and some other type of fixture? I have a single 2-bulb (2 x 24W) T5HO fixture that I run only one bulb on for my 20g. I know that it will grow everything you have. Personally, I don't see the need to replace that bulb that burned out. My plants do great with just the one and 2 is just asking for trouble you don't need. Not to mention, my fixture sits about 3" above my tank, which reduces lighting levels. My opinion anyway.

What kelvin is the bulb in the Hagen fixture? Hagen GLO, right?

I just have one fixture with two bulbs in it. I think I gave all the info I have on both bulbs but I'm not home right now so I can check this evening. The tank looks really dark and kind of purply with just the one light right now, sort of a twilightish look, and I don't really like that for all day every day.