I'm not pro ballot, I'm really not sure what it's supposed to accomplish.
IE obviously wasn't hampering competition, it's free and almost on every computer and we still ended up with at least 4 clearly superior browsers.
IE doesn't have anywhere near 100% market share.
The only reasons I can see the EU to have a problem would be standards and security issues. In which case, the more appropriate response should not be veiled under consumer choice, but to mandate that every computer sold comes with a certain level of security or web features/performance. Mandate that every computer have a browser with less than a certain number of unresolved major security issues or a certain score on the ACID3 test or that supports some other criteria.
It'd be more beneficial to whatever ecosystem the EU is trying to build, every computer would have a browser that supports the latest open standards (thus no barrier to competition), individual computer manufacturers and browsers could work out their own deals (or even let the user pick when the computer is purchased), and it would be a much stronger incentive for Microsoft to make their browser standards compliant, rather than built around their own proprietary ecosystem.
Heck, I'm surprised more PC vendors don't include alternative software more often to make their PCs stand out. Make Firefox a key feature, or offer openoffice as the only PC company to offer a free office suite. It'd be way better than the crapware that's been loaded on PCs in the past.