The world is not a perfect place. The West does need spies and it does need an infrastructure to support them and gather intelligence.
However, we should remember who we actually need to be spying on. Nation states, failed states, and yes terrorist training camps and what not.
What we should not be engaging in is dragnet surveillance where everyone is entered in to some giant database. This is a really bad idea for a number of reasons.
Firstly, the databases are not really likely to be that useful. Prism didn't stop the Boston Marathon bombers. You might have every text, every phone call, every e-mail but if you can't spot the connections it doesn't help you.
Second, the massive database is a security risk in its own right. The NSA might think the Snowden leak is bad but it's child's play compared to what would happen if somebody leaks that database! You can bet your bottom dollar a shit-storm a 100% times the size would ensue. It might even threaten the agency's continued existence.
Third, the database could be hacked by a foreign governments. This in itself is a giant risk that dwarfs the one outlined in the second paragraph. China getting access to wiretaps on US businesses? Does no-one in the security community see what a giant hole they're making in the West's security?
This leads nicely to my fourth and final point. I do get the impression from the Snowden leaks that the competency of these organisations is being called in to question. It's clear they don't know what Snowden took; they don't know what he knows and what he doesn't. This is why he's catching them at so many lies. They make one statement, he leaks another document that shows them they're full of shit.
This final point is perhaps the most damning. They've built a giant system they can't audit! If they don't know what he took when he's just a fairly junior contractor, we have to assume other nation states have thoroughly penetrated the system and already stolen Western secrets!
They're clearly not competent enough to run such a system and it should be shut down on grounds of national security.