Ok, well red lips are more than a trend, I suppose. All the same, they are very popular right now. In my opinion, though, it's always a good time to sport classic red lips.
The models at the Gucci and Dior Spring 2011 shows all sported this classic look. (If you have seen the Dior show, go watch it now! The dresses are possibly the most beautiful things ever created.)
I prefer a warm red, but most people like a cooler shade. I think it is mostly up to preference. If you like warmer tones, try Revlon Super Lustrous Lipstick in "Ravish Me Red." If you like the look of cooler reds, try "Fire & Ice."
Red lips can be quite overpowering, so it's best to keep the rest of your look simple. Go for a natural looking shadow and a little bit of mascara.