THE BEST COMPANIES TO WORK FOR IN AMERICA: Proctor & Gamble, the $30 billion consumer-products company, has the best employee benefits in the nation, according to a newly released survey by MONEY Magazine. P&G beat out IBM for the top spot this year, after Big Blue began charging employees for health benefits for the first time in 38 years. The survey, in the November issue of MONEY, called P&G's benefits unusually generous. For example, the company makes contributions to each employee's profit-sharing plan that start at 5% of pay and rise to 25% after 20 years. P&G also offers inexpensive medical coverage, with three managed-care options and a menu of insurance programs. IBM held onto second place in the ranking with a suite of perks that includes up to $250 reimbursement each year for an approved exercise program. Rounding out the top 10 companies were, in order, Chrysler, Citicorp, John Hancock, Quaker Oats, MCI, AT&T, Merck and Bell Atlantic.