I have 2 bachelor's degrees, one in biology and another in computer science, in addition to graduate degrees.

Honestly, I am a more competent bioinformatician than those with just one bachelor's degree.

From a career advancement perspective however, Devon Ryan is absolutely right.

Even though those who work with me recognize that my dual degrees make me a very competent bioinformatician, it does not in any way advance my career.

I have exactly the same position and salary as a bioinformatician with one undergraduate degree.

I don't have a PhD, and I would be FAR better off with just one undergraduate degree and a PhD, rather than two undergraduate degrees and a motley collection of graduate degrees.

I don't think a second BA will get you anything professionally (though if you're still an undergrad and can double major then that might be worth your time). If you're already a grad student then just go for a masters in bioinformatics (or CS, if you prefer).

It depends on your long term career goals. To stay, and especially to advance, in academia, I'd say a PhD is a must. A PhD is also the only degree recognized world-wide so it gives you access to a global job market should you be interested in moving abroad. Also, a CS degree can get you a higher salary than a biology one and is more marketable outside academia.