I don't much like the economy in 4e.
Now, it's important to note that the 4e economy does -exactly- what it's supposed to. Money (treasure in general) is an alternate reward system which, unlike XP, is fairly fungible but is still bounded by the general progression of things. That is to say, money is really just a system for maintaining gear, and gear is an essential part of a 4e character, so money is really ust another stat. As an abstraction, it works very well for 4e's purposes. It's neat, tidy and very efficient.
The problem is that, like my history, I like my economics to be kind of sloppy. It's very much a subjective thing, but to me it's an essential part of a living-breathing world. But doing that in games is tricky.
The first complication is that there are really two problems, and they need to be handled differently. The first is, curiously, too much money. 4e keeps this in check by keeping money fairly regimented and by guaranteeing that the increase in costs as you level up (as well as a few intentionally inefficient transactions hardcoded into the system) keeps you from stockpiling cash to get vastly superior gear, and that's kind of a shame because it removes a lot of other options. Older versions of D&D had very specific (and to my mind, quite fun) rules for what you could do with that money, the big one being to build strongholds, forts and such. While it might be a little silly to get excited about buying imaginary real estate, I have to admit that I spent a lot of time pricing out castles in the old DMG, and it was a lot of fun.
The specifics of how the money gets spent aren't hugely important - castle rules are neat, but they're chrome - but the underlying idea is an important one: large amounts of money impact could be used to impact the setting. Maybe the impact was that you bought a town, maybe it was that Danny ocean was coming after your million GP hoard, maybe it was a big tax bill. Money was part of the world, and 4e's tidy solution removes that, and you really don't want to mess with it. Money is balanced as tightly as XP in 4e, and letting players save up to buy castles can wreak havoc when they decide to spend the money on gear.
The second complication is at the other end of the spectrum. It's hard for 4e characters to be convincingly broke, because "broke" and "Encased in arcane armor of mithril and cold iron" don't really go hand in hand. Now, while the too much money issue is something of a setting concern, too little money is a flavor one. I admit that I come from a school of Rolemaster and Fritz Leiber, where fighting dangerous things for questionable rewards is something people do because they can't pay a bar tab, or because the alternative is getting a real job. Desperation is easy to achieve with a tight-fisted GM and a greedy world, but it's a tonal shift that not every table is going to enjoy.
Now, it's not all doom and gloom. 4e's system also saves us all from adventuring parties who go through dungeons like locusts, looking to steal every piece of furniture and wall fixture because there's money to be made. You laugh, but to every DM who's ever had to calculate the value of 76 torch brackets, this change is a genuine relief. Just feel obliged to mention the upside there. It's also possible to capture a lot of what I'm talking about by bypassing the economy entirely - strongholds can be won through play rather than bought, treasures can be intrinsically valuable rather than valuable for their cash, and desperation is easy to achieve when no one is particularly interested in buying your fancy pants armor and you only have a few days of food left.
That is to say, each specific issue can be addressed in turn, but the net result always leaves me cold. I like money to be meaningful, if only so that the greed of NPCs feels like something reasonable. This does not mean every game needs to be about scraping together a few copper to eat. Rather, it means that even in games of kings and princes, Shakespeare gotta get paid.
Bottom line, there's no right answer to this. 4e's system works, and I pick it out only because it's economy is vastly better thought through than most other games. But I wonder what the role of money is in your game: Is it part of the world, part of your character, or just a means of keeping score?