Just to start -
Real estate agents are PAID by the seller. However that does not in any way prevent you from having your OWN agent who is looking out for YOUR interests. That would be the "buyers" agent.
A lot of real estate agents have no idea what they are doing. Some however are well worth it. Either way, they do put up with unbelievable amounts of crap from both buyers and sellers. I do believe they are overpaid, and it isn't rocket science, but is still a useful service - and important to remember, basically free for the buyer. (both realtors will get a check for their services at your closing, which comes out of the seller's pocket. That does NOT mean your realtor is not working for you, and your realtor should (he has to) explain EXACTLY who he is working for when you first start dealing with him)
The only way you are asking to be "used" by the system is if you go straight to the listing agent when you see a house you like. (IE you call the # on the sign) In this case you may be inadvertantly paying the listing agent 6% for not doing much work. You may want to try to negotiate this down to 3-4%. Of course there is nothing WRONG with doing this and it is one of the perks of being a listing agent. But as a buyer doing this you are basically putting yourself at more risk since there is no professional who is specifically looking out for your interests.
In general, if you as a buyer have your own realtor, (which is as easy as walking into a RE office and saying "I want to look at some houses.") you are in reasonably good shape and they ARE there to help you, nothing else.
PS: My dad is a realtor, and you wouldn't believe some of the nonsense he's had to put up with... from the couple we invited to our thanksgiving dinner who a month later "tried to call but it was busy" and went and bought a $400,000 house 30 minutes later because the listing agent told them it could sell any day (lost my parents $8000 and lost themselves $4000+, not to mention that the house had been on the market for months), to the people selling a mobile home that insisted it be advertised as a "cozy villa", to those that look at 40 houses only to later "realize" that they didn't have the credit/resources to afford any of them... oh and the cozy villa folks? Listed their mobile home for 3 months with my parents, (which involves advertising, putting it in the MLS, holding open houses, checking the property occasionally) turned down offers of *$385,000* and then suddenly decided to take it off the market and "try to sell it themselves" and mysteriously someone bought it directly from them right away. Funny coincidence that happened to save them $20,000, eh?