as a capital asset, but never owns them, can't depreciate them.. and is always, always paying for hardware. Also, many leasing companies go toe to toe with the companies over normal wear-and-tear and try to force companies to pay for wear damage.. Then the leasing companies turn around and sell the assets in secondary markets.
Buy decent hardware.. make it last 5 years and depreciate 5 years. Take the capital hit upfront and leverage the tax benefits over the life-cycle of the hardware. Then take the time to sell the assets yourself on secondary markets or with a broker if you are talking large quantities.
Also, I wouldn't say leasing PCs is an investment... but then again, neither is purchasing them. It's more a necessary expense or operating cost.
* California and Virginia charge corporate property tax on capital assets.