Where's the debt crisis in Silicon Valley? The knock-on effects are all too real, but frozen credit markets have had little direct effect on business operations, aside from possibly scotching the debt-fueled sales of Alltel and Nextel. That's because technology companies are run by paranoid sorts who like to keep large cash reserves, in case some upstart renders their market obsolete. In good times, activist shareholders whinged about their parsimonious habits, but the cash hoarders are now sitting pretty — and could be set for acquisition binges.One company which listened, to its detriment, to shareholders was Microsoft. When Bill Gates ran the software company, he liked to keep a year's worth of expenses on hand, in case things went awry. Microsoft is no longer quite so stingy with its cash; it dribbles some out in dividends, and gave shareholders a $32 billion payout a few years back. Good thing it didn't shell out $44 billion for Yahoo; that deal would have left it cash-poor and debt-ridden, at exactly the wrong time. Even so, Microsoft's balance sheet is no longer the most sterling in tech. So who's got cash on hand? Here are the 10 richest tech companies, from a Yahoo Finance screening. (I left out companies, like IBM, whose cash was matched by equally outsized debts.)