I have both wordpress.com and wordpress.org blofs and I beleive the entry Staff have prepared that t3ck has linked to clearly states the differences between wordpress.com and wordpress.org blogs.
I find I have everything I need to blog here at wordpress.com. I have no interest in monetizing my blog and there are many free features and I use only a few of them. The support is excellent and my blogs benefit from traffic that flows to them via the wordpress.com global tag pages.
On the other hand wordpress.org provides free software installs only and that's it. There is a wordpress.org peer support forum but the timeframe within one can expect and answer to a support is nowhere near as quick as it is here at wordpress.com on this peer support forum. For the inexperienced self hosting blogger waiting for an answer and/or finally getting a technical answer that sails over one's head can be very frustrating. Volunteers on the wordpress.org forum expect those posting to their support be tech savvy and they do not "hand-hold" as we do here.
WordPress.org does not provide web hosting. We must pay for our own web hosting and be prepared to deal with web hosting issues, upgrading wordpress software versions, upgrading any plugins we choose to use, and figuring out where they incompatibilities are so we can correct them when conflicts arise.
All technical problems that arise on my wordpress.org install are my own responsibility to fathom and "fix" on my wordpress.org install. Here at wordpress.com all the technical help is provided by Staff free of charge to me.
Although one can montetize a wordpress.org install doing so means dealing with the affiliate and advertising issues that arise and the increase in opportunistic spam, as well as, click fraud types and the impact that fraudulent ad clicks can have on your blog, it's ranking and it's continued participation in plans like Google Adsense. In the final analysis those bloggers I know who are creating quality content and who do have good traffic don't earn much more that what's required to pay for their web hosting every year.
It's important to note that wordpress.org installs are stand alone islands. They are not part of the wordpress.com community and do not benefit from and traffic that comes to wordpress.com bloggers via they posts appearing on the wordpress.com global tag pages, and or in the Showcase and/or Off-Topic forums.
BTW I have blogged on this subject > http://onecoolsitebloggingtips.com/2010/01/13/self-hosting-whats-your-hurry/
Could you be specific about which limitations of .com bug you, and about the ways in which you want to "be creative with your blog"?
Once you answer that question I may have more that I can share with you.