Originally Posted by aysiu
More importantly, if such a new kind of malware came out that was able to exploit an Android vulnerability in this way, having "antivirus" installed would not protect you from it.
This is not entirely true, if the software uses an advanced heuristics scanner it can detect "wild" viruses and malware. Will it catch every one, no but it can reduce your risk of exposure. I have had Eset NOD32 do just this on more than a few occasions on my PC, and the files submitted turned out to be new threats.
The truth is no anti-virus or anti-malware is fool proof, none of them catch everything even if it is known.
Very good tip, by our own alostpacket! Thanks for linking to that.
In closing, considering the number of good free apps available in the Play Store if it gives someone peace of mind then go right ahead, and if it saves them anguish later even better.