Yeah, I don't think you'll necessarily find a lot of Olympus haters, but I don't know that it'd be everyone's first choice.
With the current crop of DSLRs, very high quality photos are a given. High ISO performance will generally be very good (for those who believe Canon has an edge, note the
40D review at PopPhoto where the Pentax K10D is noted for having slightly less noise at 1600)... with the Olympus maybe slightly behind but probably not too significantly. To choose a DSLR, I think you have to look at what each offers that you can't get with the others.
Canon offers a huge number of lenses and ubiquity.
Nikon offers some more build quality and almost as much ubiquity.
Pentax offers very low prices, image stabilization, extra features (top LCD, etc), and a nice kit lens.
Sony offers image stabilization, extra features (helped because their sole DSLR is slightly above entry-level), and the availability of relatively cheap older Minolta lenses.
Olympus offers the smallest DSLR, live-view, a nice kit lens, and some very interesting lens options (an F2.0 zoom? cool!).
Of course, there are negatives, too...
Canon has, compared to the others, probably the cheapest-feeling body and kit lens, and has other oddities like no RAW in Auto mode, and is a little more expensive
Nikon can't focus many of the lenses available including many desirable primes
Pentax has a small burst buffer (though the K10D fixes this and is similar in price to the XTi now) and a shortage of fast zooms, though they do exist
Sony has not so many new lenses available and they're a bit pricey
Olympus has the fewest lenses available due to no backwards compatability, they have a 4:3 aspect ratio, a relatively small and dim viewfinder, IS only in the higher-priced model, and the lenses there are seem to be quite expensive, also very little third-party lens support
Now, those are just one guy's conclusions so you should definitely take everything with a grain of salt. The point is, they're all good and there is no best for everyone.