Accept Payments Online Without PayPal?

Anyone have any advice on taking credit card payments online without using Paypal? I'm aware there are other sites like AlertPay and such, so they may be an option. Anyone have any experience with other payment processors that they can share?

I'm trying to stay away from Paypal due to all of the horror stories going around about them and a problem I had with them personally.

Here are my requirements:

1: I should have reasonably quick access to the payment--preferably instantly, but I'd be happy with 24 - 72 hours. I'll need it to pay for outsource work and I can't wait to be paid once a month or even twice a month. Weekly payment or access to the funds is about as slow as I can allow.

2: They shouldn't have a fit and close/lock the account because I get a payment of $2,500 or $5,000 from someone. They also shouldn't have any problems with me receiving payments from multiple clients about once a month--when I invoice them or the recurring billing cycle triggers--for these amounts. To begin with, I'm estimating I'll have around $10,000 - $15,000 in payments from the clients per month, with an upper limit of about $25,000 from 5 to 10 clients. This will likely accumulate over 3 - 6 months (i.e., an additional client or two per month up to 5 or 10 within six months, though I plan to acquire more eventually).

3: I would prefer something with the ease of use of Paypal, but without their bad reputation of limiting accounts and holding funds for six months. Basically, something where I sign up and I'm ready to go right then. All I have to do is get the "Buy Now" button code and stick it on my site.

I'm aware that merchant accounts exist, but I'm not quite ready for that just yet (I'm just getting the business up and running so I can't exactly show them invoices/payments from clients, etc). I'm not even sure I'd qualify and I don't want to waste the time applying only to be rejected and then going through it again with another merchant account provider until I find one that will work with me. Once things are running smoothly I'll go with this option but at the moment I'd rather not.

So, anyone have any suggestions for a third-party payment processor that would fit the above requirements, or am I out of luck?

I've also heard good things about PowerPay.biz and, while they're a merchant account, they appear to have a reputation for being quite helpful and working with you. They may be an option. Anyone have any personal experience with them?