The interesting thing about Hawala is that it provides a ready source of liquidity in local currencies. If someone was to link the two (ie, a local Hawala agent accepted a Bitcoin transfer from an untrusted source, and then moved the money via the trusted Hawala network) then almost all the problems of Bitcoin would go away.
It would also set just about every TLA agency in the US looking at you (Semi-anonymous crypto-currency which has been used in drug markets + untracable Islamic money transfer network? There's a techno-thriller plot right there). OTOH, Hawala agents seem to ignore US laws at the moment, so they might not care about this either.
Analyzing the remittances flow and their impact in the receiving countries (often more in term of %GDP than official intl development aid), it's a shame that the global average fee to "remit" is 9% and up to 12% while sending money towards Sub-Saharan Africa. 
But that's a fast moving market with several technological and business model innovations (and some YC startups too.
This last years, we have seen a lot of startups with interesting ideas based on new technologies or new business model to improve the remittances market:
Azimo (http://azimo.com), Xoom (https://www.xoom.com/), Regalii (https://www.regalii.com/ - send good instead of cash, YC), Transferwise (http://transferwise.com) and new technology like mobile banking (M-Pesa, MTNMMO) and bitcoin (buttercoin YC - http://buttercoin.com/).
Disclaimer: I work on TawiPay (http://tawipay.com) as a side-project, a comparison website for remittances services.
Have a look at Eko (http://eko.co.in). Eko is creating a network of trusted agents to service cash-in/ cash-out/ money-transfer needs of billions of non-tech-savvy customers.
The cue given by you could be an interesting opportunity for companies like Eko to explore.
Kenya's m-Pesa is a similar network of mobile money agents that indeed started accepting Bitcoins recently !
It's pretty clear that the "bitcoin<->local currency" market is a big one, but dangerous to get into because of regulatory risk. Any players who can avoid that risk somehow have a big advantage.
OTOH, if you actually want your mind blown then watch . That's a video of Brad Fitzpatrick pointing out that the Bitcoin protocol allows things like implementing Kickstarter in the Bitcoin protocol itself, or - more relevant to this discussion - things like "Party A pays Party B, but only if Party C vouches for it, and Party C cannot receive the money".
From gift giving for usage of money such as hibah to good will repayment of debt such as qardul hassan where the debtor may repay more than the principal amount, islamic banking seeks to avoid interest (riba).
People often did 'hacks' against it, such as using pawn shops. Many cities in Europe have a "Lombard Street" based on this ( http://en.wikipedia.org/wiki/Lombard_banking )
Recently, another major use is small businesses which operate as FB pages, collect money from customers using this and then send the goods. Convenient for both sides, as you avoid the hassle of depositing money in banks, or the risk of a badly implemented Online Credit Card system.
The first few pages are a very readable, understandable description of how the system works in layman's terms. Recommended read.
It's also pretty much how Western Union works.
For example: The Wikipedia article claims that the Hawala system is unusual in that no promissory notes are exchanged. However, directly after that, the article explains how extensive notes are kept on how much the brokers owe each other, and that there are some forms of final settlement between brokers. These notes on mutual indebtedness appear to play an identical role to promissory notes.
This is really no different than the final settlement between banks in the Western system, except that - as you wrote - it appears to be less regulated.
<= Wow I remember as kid, going to an "Angadia" office with my dad to transfer money. Didn't understand any of it back then.
As far as I know, Ripple still works the same way as it did then.
>However as a result of intense pressure from the U.S. authorities, widespread efforts are currently being made to introduce systematic anti-money laundering initiatives on a global scale, to better curb the activities of the financiers of terrorism and those engaged in laundering the profits of drug smuggling.
The interesting thing about this line of logical failure is the possibility that a Hawala wouldn't work to transfer funds to terrorists, they had to use a de-personalized banking system that doesn't really care what they're doing with the money, unlike the Hawala system where the agents have to consider the impact of their actions on their network/family.
Of course, such a logical failure that just happens to further secure the power of established banks against other systems, "logical failure" is a generous judgement of what was going on.