Trying to strongarm the seller depends on where you are buying and how strong the market is. Xcaliber is buying in Jersey and depending on the proximity to NYC he may be getting a deal on the house and there won't be any room for those kind of negotiations. Get too pushy with the seller and they may just tell you to bug off, especially if they aren't in a hurry to sell.
I live north of San Francisco and the market is pretty strong here right now. My parents are both in their late 70's and their house isn't even on the market. Last week a realtor knocked on their door and said their client wants to buy their house, so they're thinking of moving to a smaller place and the offer was great. South of where I am in Silicon Valley people are putting houses on the market and they're getting bid way up from the asking price.
If you have a good down payment through savings and family, and you can qualify for a loan of around $300,000, you can have monthly payments below $1,500 on a 30 year fixed. That's less than renting a decent house in my area so it's better to buy if you have the down payment.