I guess my main question is what type of host I need for my site, which will be built primarily using Joomla and a few other small apps, and for which I expect about a million page views a month.

One approach is that I should spend $80-150 or so on a dedicated server or VPS. Yet, it makes sense to me (newbie) that Yahoo's $30/month program, which offers 500GB transfer- (10,000鈥?.2 million visitors/mo., according to Yahoo) would also be a great option. Is there is one objectively right answer here? Or if either one could work, what are the pros and cons of each?

(Other service providers offer hosting at $8/ month or so, but I have found plenty of negative reviews for even the highest rated hosts. At this point, I am only considering using this Yahoo service or a VPS with my host of choice, Siteground.)

Part 2 of the question is whether Yahoo is the right place to host Joomla. Any experience with technical problems or issues there? Remember I'm a newbie, so tech support is important.

Most important for your case is the type of hosting you are using. In "normal hosting", server will be shared by others also. This means that the if other website (hosted on same server) are heavily loaded then your website will also experience slowness. This will not be the case with Dedicated Servers. You can select a host who allows to upgrade your package from normal Hosting to Virtual Dedicated Servers to Dedicated Servers so that you can switch plans as traffic grows.

Best wishes.

go check out www.1and1.com they have some great hosting plans for cheap and thier servers are stable and fast