Here's one reason why putting it in writing is best, even if forgery is possible.
People are way more likely to argue about what was agreed to, than about whether an agreement was made.
With verbal agreements, most people won't lie and say that no conversation took place. (The "whether" part.) But many people will misremember or distort the exact words that were exchanged. (The "what" part.) And those exact words are what count, legally.
Likewise, a person would have to be really slimy to claim that your signed, written contract is a forgery. Most people won't dispute that they signed it. (Again, the "whether" part.) And since it's in writing, and there simply is no room for disputing the "what."
To put it another way, getting a written agreement raises the moral and legal stakes for a potential welcher. They'd have to accuse you of forgery, instead of just shrugging and saying "I guess we remember the conversation differently."
I'm realizing now I misread the OP, and we are talking about a verbal contract-- for which I'll agree different rules apply. (Not legally, but practically.)
My question is more about whether there's any practical distinction between an informal email which contains a clear agreement to work and the "signed contract" spoken of in legend.
Practically, one difference would be in the level of detail. Contracts tend to go on at length about the finer points of the business relationship. Whereas, in an email, people would typically be much more brief.
The extra details can be very important.
For one, they help prevent misunderstandings. ("It's been three months, and you haven't paid me." "Oh, well it's our standard practice to pay all invoices within 12 months.")
Secondly, if the relationship becomes acrimonious, the details help limit the scope of a possible dispute. The more the parties make explicit up front, the less there is to argue about later.
Another difference concerns the Statute of Frauds. (http://www.lexisnexis.com/lawschool/study/outlines/html/cont...) Certain kinds of contracts--notably those above $500--require a signature of some kind. But, if you read § 6.03 in the statute, you'll see that this can be construed broadly. Often, merely including your name in an email is enough to satisfy the Statute of Frauds (http://www.internetlibrary.com/topics/statute_frauds.cfm). But if you're looking to hold someone to their word, it's safer not to rely on that.
It's better to be safe than sorry. If you want something to be binding, it's best to go with a solid contract, rather than just an exchange of emails. If you don't want to commit yourself just yet, don't assume that your emails are nonbonding. In other words, be pessimistic either way.
People are way more likely to argue about what was agreed to, than about whether an agreement was made.
With verbal agreements, most people won't lie and say that no conversation took place. (The "whether" part.) But many people will misremember or distort the exact words that were exchanged. (The "what" part.) And those exact words are what count, legally.
Likewise, a person would have to be really slimy to claim that your signed, written contract is a forgery. Most people won't dispute that they signed it. (Again, the "whether" part.) And since it's in writing, and there simply is no room for disputing the "what."
To put it another way, getting a written agreement raises the moral and legal stakes for a potential welcher. They'd have to accuse you of forgery, instead of just shrugging and saying "I guess we remember the conversation differently."