Don't use bold text, italics and underlines with impunity.
Strike one, strike two. Get out. T_T
You shouldn't feel too big not to use semantic content, nor too small to hide from it.
Then move them to the right, when you should be using CSS instead.
According to Success Criterion 1.3.1 (Info and Relationships), authors should use semantic markup wherever possible.
In HTML 4.01, the above presentational elements and attributes are considered to have no semantic meaning, and thus should be replaced with semantic elements where possible. However, also consider whether you are using the correct semantic element - if you are using bold text for normal emphasis, it may be more correct to use the "em" element and redefine it to bold text using CSS.
In HTML5, some presentational elements such as "b", "i" and "u" have been redefined to have limited semantic meaning, making them usable but only as a last resort.
Remember that presentational elements do not need to be completely eliminated, but they should be seriously considered, making sure to check whether a semantic element should be used instead. For instance, if the contents of elements such as "b" meet the HTML5 definition and do not require emphasis (as suggested by "strong" or "em"), the case can be made for keeping the "b" element. If there appears to be no semantic meaning at all, it may be more prudent to replace with a span element and style using CSS.
(The "*" represents the name of the presentational tag being questioned, with first character capitalised, eg. "I", "Big", "Tt", etc. Uses of the "align" attribute are end with "AlignAttr".)