Latin was my first foreign language, and since I started it other languages and especially Romance languages have been pretty easy grammar-wise. I study Italian, Spanish, and Persian and I've had no problems with their grammar whatsoever. Greek still intimidates me, but slightly less, as I now just see it as a little bit more complciated than Latin.
In the Romance languages you'll notice that the verb conjugations all look familiar and simpler. There's a lot of shared vocabulary too, especially with Italian. It's fun to see how words have changed or maintained their meanings from Latin, and pointing it out will make you appear smart.
Conversely, I'm quite apprehensive about the non Indo-European languages I want to learn, Arabic and Hebrew... hopefully one will follow on the other readily enough.