My wife and I are new to the paleo lifestyle, so we're going through our cabinets and getting rid of most of our flours, pastas, sugars, etc. We've got some Bob's Red Mill Garbonzo and Fava flour, and we're not sure whether to keep it or not. I know that legumes aren't so great, and I'm not at all familiar with fava beans. Is it ok to have it around, or at the very least, not nearly as bad as wheat flour/grains?
Literally, no, they're not as bad as wheat/grains. That being said, legumes still have plenty of shortcomings all on their own.
Some branches of paleo will give passes to sweet peas, fresh green beans, and/or fermented soy (tamari, miso, natto (but tofu and TSP are still no-nos)).
Paleo doesn't really go much in for baking in general (and one of the key points of any of the challenges is just don't try to create imitations of products you miss, it'll just make you frustrated).
The two most common flours in paleo cupboards are usually almond meal (good for "breading" a chicken breast) and coconut flour (for a sweet paleo pancake, coconut flour + egg). Arrowroot for thickening a sauce (but carefully, it reacts differently than wheat flour).
I have both of those flours in the fridge and use them once in a blue moon, they are a "just in case" pantry item. I cook for people who don't eat the same way I do, and will include these in muffins and stuff like that, I figure it is still better than wheat flour. You might want to look up some Weston A. Price Foundation recipes and see if there are any that include fermenting the batter or dough you'd be using to reduce the anti-nutrient load if you want to include those flours on a regular basis.
This article "To Bean Or Not To Bean, That Is The Question (Legumes, Lectins, and Human Health)" by J.D. Moyer might be of use to you in deciding whether or not to include the bean flour in your diet. I thought he did a pretty decent and quite thorough job of looking at both sides of the coin on this.