For Christmas I am going to rent a sports car for my boyfriend for the day between the Mercedes slk350 and Nissan 350z which is a better car? Also, what other cars would be good to look into renting. Thanks!

Mercedess is a sports car? i thought it was a luxury car .why dont you get him something he can use

You'll probably enjoy the 350Z alot more as far as driving experience goes. The SLK350 really isn't anything to write home about except the fact thats its a Mercedes. Now the SL65 AMG or CLK65 Black Series is a whole different machine but you may not be able to find one for rent unless you live in LA or another similar city. I'd go for the 350Z, especially if your BF knows how to drive a manual transmission. I have a Maxima myself its truly a joy to drive (Maximas the 350Z share the same motor, but the chip in the 350Z is different,). Hope you have a Merry X-mas...you kids play nice now...
Usually when you see a guy in a SLK it screams; I couldn't afford the CLK or SL. SLK's are typically womens cars.

It all boils down to class, the Mercedes without question. Porche would be another.

Owning a Mercedes slk350 can be an expensive nightmare but renting it would be a dream come true. Its soooooo cool on so many levels. The Nissan is the car you would love to own but the mercedes is the one to have for a special occasion.
What a great girl-friend to think of such a great gift. Having you is already enuf. I hope he appreciates you!