I used to think guppies were absolutely boring, but my experience was limilted to feeder guppies (which I used to buy long long ago for my angels). I bought some Fancy guppies not too long ago as cycling fish (yes, I know better now and will use a fishless cycling methods from now on) and I've come to really like them. They are not overly bright, and are rather piggy eaters, but are playful, colorful, and VERY friendly (probably hoping for more food!!!).
Also, Cherry Barbs might be okay with angels. They don't seem to nip fins, and are probably large enough and fast enough to avoid being eaten by angels... What do more experienced angel-keepers think?
In the past when I kept angels, they seemed to do best in soft, slightly acid water (pH of 6.6 to 6.8) with rocks/caves (for other tank dwellers to hide in), driftwood, and plenty of plants! My angels really seemed to do best when I had a fair number of plants in the tank... Also, be careful to ALWAYS treat your water (i.e., with Prime) when doing a water change, and carefully match water temperature before adding the replacement water. Angels can be really delicate at times. One I had was amazingly hardy (even surviving a 5-6 hour trip home when I graduated from college), but others seemed a lot more sensitive...