If you are looking for shared hosting company then they will all say Unlimited, just because they all had to take the same marketing strategy when the first company said that publically. Unlimited really means unlimited until you are going to abuse it with traffic and disk space. At that point they would offer you to upgrade to the VPS most likely. Normally servers are loaded with shared accounts until the overall load starts to spike. The number of shared accounts depends on the type of the sever hardware - the more powerful, the more accounts would fit.
From the performance standpoint running a wordpress blog with 10,000 visitors per day won't effect anything on shared hosting.
You can also offset your css, js, images load with implementation of the CDN (like MaxCDN for example)- its extremely easy to turn on and your site will load fastest to anyone in the world, the only load to your shared account will then be at database query - which is pennys compared to loading the image for your visitor.
So long story short - you should be ok with shared hosting from anybody in the top5 listed under Best Hosting tab - they are all great hosting companies, great support, reliable and people are happy. Trust me, if there's a problem, reviews will reveal it right away. They are all listed on BBB.org and US companies.
Otherwise if you want something more expensive for the piece of mind, go with the VPS, but from what I've read in your question you don't need it.