I always fall back on this solution. Not too hack-ish and gets the job done.
EDIT: I should point out that you might achieve the effect you want with the following code (forgive the inline styles; they should be in a separate sheet). It seems that the default alignment on an image (baseline) will cause the text to align to the baseline; setting that to middle gets things to render nicely, at least in FireFox 3.
<div>_x000D_
<img src="https://cdn.sstatic.net/Sites/stackoverflow/company/img/logos/so/so-icon.svg" style="vertical-align: middle;" width="100px"/>_x000D_
<span style="vertical-align: middle;">Here is some text.</span>_x000D_
</div>
_x000D_