Rails（3）服务器 - 现在用什么？

I've been using Ruby Enterprise Edition and Passenger (for Apache, since I run Apache anyway for other things) for some time, but I'm wondering if there's a new trend about what to use on servers nowadays. For example I've heard about Thin, Unicorn... I also know that 1.9.2 is faster than REE, but I wonder about RAM consumption. I'd rather have it consume less RAM even at the expense of some speed.I've been using Ruby Enterprise Edition and Pas