A subjective response. My own is one of the three crossfires I own. The 2007 Special Editions are the best. I have no regrets in buying it and would absolutely do it again. They have SRT style wheels, are resale red, and are convertibles. BTW, earlier year Crossfires with the medium gray interior are subject to the paint peeling of interior trim. I also have a Limited 2004 coupe with that problem, and now a 2006 limited coupe with only 4,700 miles which has a sticky feel to just the medium gray interior trim paint. I'm very careful with it so it does not peel.
A more serious response, from a collector perspective, would be the low volume SRT6 versions with the added horse power. I initially avoided them because of more maintenance issues on the engine and costlier parts. I also didn't care for the big wing on the back. Not everyone cares or needs the added horse power to enjoy their Crossfire, and when you are looking for possible future appreciation you then avoid driving the car which would devalue it with more miles and wear and tear. I've since softened/changed my opinion and would like to have an 06 SRT6 convertible if the right opportunity came up, but would not be disappointed if it didn't.
You didn't say why you were asking. There are many reasons to buy a Crossfire, and reasons why to enjoy them. Unfortunately, Daimler Chrysler made many mistakes with the Crossfire which resulted in bad press. Fortunately for us we have been able to buy great cars at very good prices.