I have not answered that myself and as such I am asking myself that question. I certainly like the fact I am working on new things and getting to branch out into areas I might not normally get a chance to work with. That said, there are some downsides as well.
At first you are going to see that hourly rate and say, wow that is a lot per hour. Hold on there though. Most likely that rate does not include paid holidays or vacation time. So you need to take your salary/year based on 40 hour work week (if your contract is 40hr/week) and then minus the vacation time you'd like to have and the holidays you won't get paid for. Check up front to find out if you can work holidays. If you can't, each of those days off is 8 hours of pay you are missing.
That adds up to make your hourly rate start to not look so good.
The other thing to consider about your rate and contracting is are you going to go with a firm (I have) which makes finding contracts easy but eats into your rate. Meaning, that the contracting company is taking a cut of the rate per hour you are being paid. Now, you don't see that taken out of your pay cheque, but needless to say, if you want to do the harder path and run the business side of things then you can make more contracting on your own.
Also, do you want to gain ownership of something and make decisions about the design and direction of the product? Then contracting, unless it is an architectural position, may not be your thing. So far I have seen that contractors in general are paid to get stuff built. That is great if you don't want to have ownership and just like doing new things each day. Not so cool if you like to have a say in the product and help design what you ship.
I am still out on this one. There is certainly an advantage to just being a grunt, getting stuff done. It is amazing to see the amount of code/progress you can make each week just implementing and not planning. That said, it's nice to have some more skin in the game with the design of a product.
Some other things to keep in mind is that you (most likely) will not get matching contributions for retirement or other benefits. That is fine if you are getting paid a high enough rate. If not, then you are missing another chunk of cash.
Contracting has the allure of new projects, less maintenance of products, and the ability to make more hourly. The truth is that the new projects and less maintenance of long term code comes at the price of ownership in the product. The high hourly rate hides the visible benefits of full time positions that you might not consider.
So, like many things in life, it all comes downs to tradeoffs. Which ones are you willing to make and what do you want out of your job.