My favorite plants keep changing. They all have their good and bad qualities. I think my top 3 favorites (at the moment) are:
1. red Ludwigia
2. Anubias nana
3. Water Wisteria
honorable mention to green myrio.
The only thing I don't like about the red ludwigia is that it grows really tall, but it takes a while for other sprouts to come off, so basically they're just super long stems with small leaves and look a little awkward when they hit the top of the water and start growing sideways. I still really like it, though. You need high light in order for it to stay red, though.