Please do use Arial. I find it better than about 95% of the choices done by "people that care about typography". Or even better, let other people that care about how their web experience looks chose for themselves. I had the habit of not allowing websites to use their own fonts, but since about 5 years this has led to so much breakage because apparently I HAVE to download 700kb of fonts to render the site properly.
Even though browsers have started rendering web fonts OKish the last couple of years, I still encounter sites daily where I would prefer a monospaced font to whatever abomination the site is using. A bad choice of font is worse than an ok font that make a minuscule group think "this guy doesnt care about typography".
... And don't get me started on ligature abuse...
Edit: for some reason though, people seem to produce better in-print material than web material. Maybe the tooling is better, or people just think it through better.