GOOG -58% YTD, AAPL -52.16% YTD, MSFT -40.45% YTD, EBAY -60.68% YTD

The ongoing financial crisis is fast beating even tech sector stalwarts into whimpering submission.

Google (GOOG) shares have not fallen below $300 since October 2005. Yet they slipped more than six percent to close at $291 Wednesday, driven downward by a marked slowdown in online advertising. They began the year trading at $724.80, so their journey to $291 is a humbling descent.

It’s also one we’re seeing played out in varying degrees of severity across an industry, whose members all seem to be trading near their 52-week lows or worse (click on the charts below).

Much worse, in Intel’s (INTC) case. Shares of the tech bellwether fell to a 12-year low of $12.36 Wednesday after it slashed its fourth-quarter revenue forecast.

And worse still for Sun (JAVA) whose share price is down about 98 percent since the height of the dot-com boom. At $4, Sun’s stock is trading at a 13-year low.

Meanwhile, Yahoo’s (YHOO) shares are hovering around $10, a price they’ve not seen since 2003. EBay’s (EBAY) are trading at a little over $12, a six-year low. And at $20.30, shares of Microsoft (MSFT) are revisiting market territory they’ve not seen since 1998.

And then there are the year-to-date declines.

• Google, down -58% YTD
• Yahoo, down -56%YTD
• Apple, down -52.16% YTD
• Microsoft, down -40.45% YTD
• Intel, down -47.75% YTD
• eBay, down -60.68% YTD
• Amazon, down -50.02% YTD
• IBM, down -23.46% YTD
• Sun, down -77.77% YTD
• Hewlett-Packard, down -34.13% YTD
• Cisco, down -36.53% YTD

Said Citigroup analyst Mark Mahaney in his latest research note, “[this is] almost surely the worst economic environment in our collective lifetimes. We didn’t uncover a single source that thought business trends were going to improve in the foreseeable future.”

Obviously.