First off; I don't know of the nature of the interpersonal relationship between you and your roommate, and I don't really care, but I will say that your use of that term was a red flag to me, and it will be so to a bank; buying a home is a big deal that you normally do not undertake with just a "friend" or "roommate". "Spouses", "business partners", "domestic partners" etc are the types of people that go in together on a home purchase, not "roommates". Going "halvsies" on a house is not something that's easily contracted; you can't take out two primary mortgages for half the house's value each, because you can't split the house in half, so if one of you defaults that bank takes the house leaving both the other person and their bank in the lurch. Co-signing on one mortgage is possible but then you tie your credit histories together; if one of you can't make their half of the mortgage, both of you can be pursued for the full amount and both of you will see your credit tank. That's not as big a problem for two people joined in some other way (marriage/family ties) but for two "friends" there's just way too much risk involved.
Second, I don't know what it's like in your market, but when I was buying my first house I learned very quickly that extended haggling is not really tolerated in the housing market. You're not bidding on some trade good the guy bought wholesale for fifty cents and is charging you $10 for; the seller MIGHT be breaking even on this thing. An offer that comes in low is more likely to be rejected outright as frivolous than to be countered. It's a fine line; if you offer a few hundred less than list the seller will think you're nitpicking and stay firm, while if you offer significantly less, the seller may be unable to accept that price because it means he no longer has the cash to close on his new home.
REOs and bank-owned properties are often sold at a concrete asking price; the bank will not even respond to anything less, and usually will not even agree to eat closing costs. Even if it's for sale by owner, the owner may be in trouble on their own mortgage, and if they agree to a short sale and the bank gets wind (it's trivial to match a list of distressed mortgaged properties with the MLS listings), the bank can swoop in, foreclose the mortgage, take the property and kill the deal (they're the primary lienholder; you don't "own" your house until it's paid for), and then everybody loses.
Third, housing prices in this economy, depending on market, are pretty depressed and have been for years; if you're selling right now, you are almost certainly losing thousands of dollars in cash and/or equity. Despite that, sellers, in listing their home, must offer an attractive price for the market, and so they are in the unenviable position of pricing based on what they can afford to lose. That again often means that even a seller who isn't a bank and isn't in mortgage trouble may still be losing thousands on the deal and is firm on the asking price to staunch the bleeding. Your agent can see the signs of a seller backed against a wall, and again in order for your offer to be considered in such a situation it has to be damn close to list.
As far as your agent trying to talk you into offering the asking price, there's honestly not much in it for him to tell you to bid higher vs lower. A $10,000 change in price (which can easily make or break a deal) is only worth $300 to him either way. There is, on the other hand, a huge incentive for him to close the deal at any price that's in the ballpark: whether it's $365k or $375k, he's taking home around $11k in commission, so he's going to recommend an offer that will be seriously considered (from the previous points, that's going to be the asking price right now). The agent's exact motivations for advising you to offer list depend on the exact circumstances, typically centering around the time the house has been on the market and the offer history, which he has access to via his fellow agents and the MLS. The house may have just had a price drop that brings it below comparables, meaning the asking price is a great deal and will attract other offers, meaning you need to move fast. The house may have been offered on at a lower price which the seller is considering (not accepted not rejected), meaning an offer at list price will get you the house, again if you move fast. Or, the house may have been on the market for a while without a price drop, meaning the seller can go no lower but is desperate, again meaning an offer at list will get you the house.
Here's a tip: virtually all offers include a "buyer's option". For a negotiated price (typically very small, like $100), from the moment the offer is accepted until a particular time thereafter (one week, two weeks, etc) you can say no at any time, for any reason. During this time period, you get a home inspection, and have a guy you trust look at the bones of the house, check the basic systems, and look for things that are wrong that will be expensive to fix. Never make an offer without this option written in. If your agent says to forego the option, fire him. If the seller wants you to strike the option clause, refuse, and that should be a HUGE red flag that you should rescind the offer entirely; the seller is likely trying to get rid of a house with serious issues and doesn't want a competent inspector telling you to lace up your running shoes.
Another tip: depending on the pricepoint, the seller may be expecting to pay closing costs. Those are traditionally the buyer's responsibility along with the buyer's agent commission, but in the current economy, in the pricepoint for your market that attracts "first-time homebuyers", sellers are virtually expected to pay both of those buyer costs, because they're attracting buyers who can just barely scrape the down payment together. $375k in my home region (DFW) is a bit high to expect such a concession for that reason (usually those types of offers come in for homes at around the $100-$150k range here), but in the overall market conditions, you have a good chance of getting the seller to accept that concession if you pay list. But, that is usually an offer made up front, not a weapon kept in reserve, so I would have expected your agent to recommend that combined offer up front; list price and seller pays closing. If you offer at list you don't expect a counter, so you wouldn't keep closing costs as a card to play in that situation.