Don't sweat the small stuff—it kills deals. Never negotiate cosmetic flaws (like ugly paint or carpet) or personal property (furniture and curtains). You saw those when you made the offer, and nitpicking them makes you look difficult. Most importantly, if you are buying "As-Is," do not ask for credits on systems that are simply old. The inspection is for finding broken things (like a leak), not for getting a free upgrade on a working 15-year-old AC unit.
Your Realtor should be able to advise you on the current market conditions, and whether a lower offer is acceptable or not. That being said, some things to consider when putting in an offer are whether or not the items that you would need to pass a 4pt inspection are in good working order. Those items are the roof, plumbing, electrical and HVAC. If these items are older and would potentially prevent you from obtaining homeowners insurance, due to the age and/or condition of them I would consider putting an offer to offset those costs.
If you are hoping to buy a house, you likely have a budget in mind. Hopefully, that budget includes fees that come with the process, not just the purchase price. The good news for buyers is that they aren't directly responsible for paying their agent. Agent fees usually fall on the seller.