Don't be fooled by just watts because even though on paper it may say 100W x5 it's not always the case. Recievers are amplifiers, not wattifiers... something to also remember.
I would steer clear of lower-end Sony product, most of the people here will tell you the same because of the build quality put in to them is close to crap.
The Onkyo TX-SR501 is a decent unit.
At the entry-level range, around $150-300 I would recommend the Harman/Kardon AVR-125 reciever. You can find it at SoundCity which is a reputable dealer. If you look at
www.soundcity.com you will notice that the reciever is refurbished but from everyone who has bought a HK refurb I have never heard of anyone having a problem.
Not to mention Harman takes that extra step to provide excellent customer service, always a plus of a company, which none really do take that extra step these days.