I'd divide that lot up as follows:
Excellent - Gascoigne, Stewart (goal in FA Cup final and sold at a profit)
Good - Armstrong (62 goals in 173 games is pretty good), Popescu (played one season, scored a winner against the Goons and we made a profit when we sold him to Barca)
Average - Ferdinand (scored some goals but silly to spend 6m on a 30 year old), Durie (scored a few goals and we sold him to Rangers for about what we paid), Bent (got to give him a chance)
Ugly - Rebrov (Hoddle destroyed him and we lost 11m quid), Dumitrescu (didn't last a season, although we got 1m from West Ham for him)
The key point on a lot of these players is we spend big and got nothing back as a transfer fee in return!