Alone on the market as a rear-engine, high-performance luxury car, the Porsche 911 has no exact rivals, but there are many cars on the market that seek to deliver a similar mix of fun, practicality, and style.
The 2013 Chevy Corvette is perhaps one of the most frequently pitched alternatives to the 911, as it's about the same weight, also quite useful thanks to a relatively large hatch-access cargo area, and is very powerful and capable in the corners.
The high-end Z06 and ZR1 models can take on the top of the 911 range, but no Corvettes offer all-wheel drive or the level of interior refinement and equipment Porsche offers.
BMW's 6-Series is another sport coupe that cuts a unique image and offers plenty of performance, but its balance is tilted much more heavily in the comfort/luxury direction.
Even with a potent twin-turbo V-8 engine in the top models, including the M6, the heavy and relatively large 6-Series is no match for the 911 on a winding road.
Godzilla, or as it's properly know, the 2013 Nissan GT-R, is another car that some buyers might consider in place of a 911.
Purchase price of the GT-R is competitive with the lower end of the 911 range, while performance is on par with or better than the top-end.
That said, the GT-R achieves its performance through electronic wizardry as much as through well-tuned chassis and suspension design, and it therefore lacks much of the visceral feel of the 911.
Finally, there's the Jaguar XK.
Like the 6-Series, the bulk of the XK range is biased much more clearly toward luxury and comfort than sport, and while it may have an edge on the 911 in these areas, even the top-end XKR-S isn't quite as sharp and rewarding on track as the 911.
In the end, any of these cars can be good purchases, provided they meet your desired balance between functionality, looks, performance, and comfort.