In this discussion it is probably better to focus on median household income...which is probably the point the two earlier posters were speaking of when they commented we are worse of.
from 1975
Year No. of Households Real $ Inflation Adjusted $
2009* 117,500,000 $48,500 $48,500
2008 117,181,000 $50,303 $50,303
2007 116,783,000 $50,233 $52,163
2006 116,011,000 $48,201 $51,473
2005 114,384,000 $46,326 $51,093
2004 113,343,000 $44,334 $50,535
2003 112,000,000 $43,318 $50,711
2002 111,278,000 $42,409 $50,756
2001 109,297,000 $42,228 $51,356
2000 108,209,000 $41,990 $52,500
1999 106,434,000 $40,696 $52,587
1998 103,874,000 $38,885 $51,295
1997 102,528,000 $37,005 $49,497
1996 101,018,000 $35,492 $48,499
1995 99,627,000 $34,076 $47,803
1994 98,990,000 $32,264 $46,351
1993 97,107,000 $31,241 $45,839
1992 96,426,000 $30,636 $46,063
1991 95,669,000 $30,126 $46,445
1990 94,312,000 $29,943 $47,818
1989 93,347,000 $28,906 $48,463
1988 92,830,000 $27,225 $47,614
1987 91,124,000 $26,061 $47,251
1986 89,479,000 $24,897 $46,665
1985 88,458,000 $23,618 $45,069
1984 86,789,000 $22,415 $44,242
1983 85,407,000 $20,885 $42,910
1982 83,918,000 $20,171 $43,212
1981 83,527,000 $19,074 $43,328
1980 82,368,000 $17,710 $44,059
1979 80,776,000 $16,461 $45,498
1978 77,330,000 $15,064 $45,625
1977 76,030,000 $13,572 $43,925
1976 74,142,000 $12,686 $43,649
1975 72,867,000 $11,800 $42,936
So yes median household income has increased since 1975.....however when you factor in that in 1975 there was much more single income households, and people drove far less to work / home / shopping etc; it may not be that far off to say we were better off back then at least at the level of perceived economic stress