I've typically used iFrames to display Marketo forms on a Wordpress site. I like that forms will prepopulate, progressive profiling still works and IMO it's less effort than dealing with the raw HTML.
There are 2 wordpress plugins that I've not utilized but am trying to learn more about: Contact Form 7 and Gravity Forms which both can integrate with Marketo. I just started a discussion so you may want to keep an eye on that.
I strongly agree with Kyle, iFraming Marketo forms will retain all native features while keeping the website's original look&feel.
Most tracking plugins rely on the underlying application, typically a Content Management System, rather than explicitly adding the Munchkin script. That mitigates the risks to jQuery versioning conflicts.
As of October 2013 Marketo is running jQuery 1.8.2. Google runs 1.9.1. The Asynschronous and Asynchronous jQuery Munchkin calls, taken directly from Admin - Munchkin, fail because a different library version is already loaded in the browser.
A very good plugin not actively maintained but still viable is
I just want to share this with you. Hoosh Marketing has a WordPress Marketo Integration Plugin. The solution allows you to use Marketo-enabled forms in Wordpress, prefill forms, send automated blog updates and digests and explore advanced features for website personalization.