Playing on a 37" HDTV in 1080p (1920x1080) at 7'-8'6" distance away in a comfortable recliner chair is absolutely glorious, but using steam, and reading text in steam is another story. Steam's 14 point font is very difficult to read, so I've found a solution.
Edit C:\Program Files (x86)\Steam\resource\styles\steam.styles
Open in notepad and use the Replace... feature.
Just type in font-size=14 and replace all with font-size=16
18point was a little too large; 16 seems to be a nice balance.
It's only a very slight change by 2 font points. But trust me. This makes all the difference in being able to read conversations in the steam app.
Hope this helps anyone else in a similar situation; and have some before and after screen caps!