Helmet - Anything Snell 2010 and/or DOT approved that fits properly. Higher end helmets (Shoei, Arai, Shark, AGV, etc) are generally lighter, have more comfortable liners, and better shield/vent hardware. They do NOT protect better simply because they cost more.
Gloves - Gauntlet style with hard armor on the knuckles and thick leather on the palm.
Jacket - Textile/Leather with shoulder and elbow armor
Back Protector - Built into the jacket or in addition
Pants - Armored overpants (textile/leather) or armored jeans. (Imagine running at full speed and doing a baseball slide on asphalt....Now imagine doing it at 25-65mph...)
Boots - Purpose built motorcycle boots with ankle protection.
Look for closeouts on previous year(s) equipment. You can find closeout helmets for less than half of MSRP, and that includes the higher end brands. The same goes for all of the other gear you will need. Expect to pay @$1000-1500 to get a full set of gear. Gear can last 5+ years if you take care of it, and don't crash in it. So it is money well spent.