Internet service provider (ISP) iiNet is doing nicely at the moment -- it had over $1 billion in revenue last year. Its annual accounts also give an interesting indication of how it spends money on IT.
Here are iiNet's capital expenditures for the most recent financial year:
In capex terms, you'd expect spending on growth projects to be higher than for maintenance -- much of that will end up as operating expenditure instead. Just under 30 per cent of general IT expenditure is for maintenance, which seems like a healthy proportion some other businesses would envy.