I had the same problem when i was first looking to buy my first dslr.
About the low light shooting, I found when i first started shooting low light with my new dslr, i was really and i mean really disappointed with the results, the on-board flash was too harsh, and even if i bumped up the iso it was still disappointing, especially with fast moving stuff like kids.
You have to think that any kit lens you get with your fist dslr, whether it is canon, Nikon or Olympus your largest aperture is going to be around f3.5 so you will have to invest in a faster lens to get better low light results. Yes some deal with noise better than others but i think the difference is negligible... what you really need to be thinking is getting an external flash that recycles fast, i would avoid the fl-36 as i get so frustrated with the recycle speed, the metz alternative is apparently better or spend a bit more get the old fl-50 (which are much cheaper now), Also they have AF assistance to help you focus faster.
If you do like the feel of Olympus cameras you have to then see if you want image stabilisation (e-510) or want smaller size (e-420, get that instead of the e-410) because apart from that they are essentially the same.
What sold me was the price and the size, i ended up getting an e-400 and twin kit lens from Currys for about £400 with 4 years accidental insurance, and i still love it.
If you were to go for Olympus absolutely with no question get the double kit lens it is a great start as you have a range from 14-150mm (28-300mm eqiv). Then i would get a flash for those low light situations.
The only one down side i see with Olympus is that it is harder to get second hand lens, either because the glass is so good and no one wants to sell or less people own olys then canon and Nikon users.
Sorry for the essay, i’m hope i have answered your questions...
Olympus e-400/14-42mm/40-150mm/Raynox DCR-250
Olympus FL-36 flash