@louie540 -- no, no it isn't. B and I do not MEAN the same thing as STRONG and EM -- though a lot of people seem to think they do just because they have the same default appearance... They are NOT deprecated, and they sure as shine-ola aren't obsoleted in the specifications... Despite wild claims to the contrary.
The default appearance has jack to do with what a tag MEANS -- as one of my old signatures said, if you're choosing tags because of what they look like, you're probably choosing the wrong tags.
For the question at hand, it depends on what the content IS and WHY you are applying those tags to it.
An example a friend of mine made a while back:
<b><i>GURPS,</i></b> <b>Steve Jackson Games'</b> flagship role-playing game, was first released in 1985. Several licensed adaptations of other companies' games exist for the system, such as <b><i>GURPS Bunnies and Burrows.</i></b> However, <b>SJ Games</b> has no connection with <b>Wizards of the Coast</b>, producers of the <i>Dungeons and Dragons</i> RPG. <em>No <b><i>GURPS,</i></b> content is open-source.</em> <strong>Do not plagiarize <b>SJ Games</b> work!</strong>
Which does a great job of showing the who/where/why of when to use B, I, STRONG and EM, and how they ALL still serve a semantic purpose. Strong and EM apply extra "emphasis" to the content around them -- it's why screen readers read them differently! B and I are hooks for when the grammatical presentation of text is different, without applying a specific semantic meaning -- it's one of the few times presentation in the markup should and does make any sense. You're not "adding emphasis" when it's a company or book title, so EM (emphasis) or STRONG (MORE emphasis) make no sense.
Oh and if that's CONTENT like flow text in the main part of your document, declaring your fonts in PX is a miserable failure at accessibility.