I would like to have a ranking for known brand names of watches for
man, which will include the list of 20 brand names in order, from the
most reputable one and down to others.

I don't know what 'reputable' would mean in this context. Most watches
tell time quite well. I've had watches that cost five dollars that
kept time as well as a Rolex. Thanks to the quartz mechanisms of
modern watches, accuracy no longer requires great expense. The expense
usually has to do with the jewelry aspect and status hype of the
watch, not its function.

I managed to get you toe top 10 brands, hope this would be useful ---

List of top 10 brands:

Rolex
Seiko
Omega
Citizen
Cartier
Fossil
Casio
Invicta
Timex
Breitling


List of other famed watch brands:

Accutron
Activa
adidas
Armani
Armitron
Baume & Mercier
Bedat
Breitling
Bulova
Burberry
Bvlgari
Calvin Klein
Caravelle
Carrera
Cartier
Casio
Chase-Durer
Chopard
Christian Dior
Citizen
Concord
Corum
Croton
Daniel JeanRichard
Diesel
Disney
DKNY
Dunhill
Ebel
Eddie Bauer
Elgin
Elini
ESQ
Fendi
Festina
Field and Stream
Fossil
Franck Muller
FreeStyle
G-Shock
Geneva
Gevril
Givenchy
Grimoldi
Gucci
Guess
Hamilton
Haurex
Hugo Boss
Invicta
IWC
Jacques Lemans
Kenneth Cole
Lancaster
Locman
Longines
Lucien Piccard
Luminox
Marc Ecko
Michele
Mido
Movado
Nautica
Nike
Nixon
Oakley
Omega 
Panerai
Paul Frank
Perry Ellis
Philippe Charriol
Pulsar
Rado
Raymond Weil
Relic
Rip Curl
Rolex
Seiko
Skagen
Smith & Wesson
Suunto
Swatch
Swiss Army
TAG Heuer
TechnoMarine
Timberland
Timex
Tissot
Tommy Bahama
Tommy Hilfiger
Tourneau
Troika
Vanceur
Versace
Vizio
Wenger
Wittnauer
Zodiac
Jaeger-LeCoultr

pinkfreud - thanks. I meant the high ststus brands, such as Rolex etc.

Tommyng - thanks for the lists, very usefull. Can you pls advise what
is the source for the lists?
Thanks in advance.

Status is highly subjective.  For instance, a Rolex will might win you
friends amongst snooty elitists and gold-digging women, where as a
vintage 80's casio calculator watch will draw praise from seasoned
computer/technology geeks.

As a geek-digging woman, I'd sure go for the guy with the 80's Casio
calculator watch over some show-off wearing a Rolex.

I think that status is more objective then subjective - I do not think
that anyone will say that Casio has a better reputation and status
then Rolex. Then, every one can decide if to go for the Rolex or Casio
depending on his subjective preferences and, obviously, budjet.

I am looking for some info which will tell me what are CONSIDERED more
reputable between Seiko, Citizen, Tissot, Longines, Sector etc.

I still think 'reputable' is an odd term to use. To me, a watchmaker
is reputable in relation to the accuracy and durability of the watch.
I suspect that what you mean is something very different, related to
the hype and image associated with overpriced "status" watches.

correct ! can you assist on this please?

Oh, darn, now I've got to find a Casio calculator watch to impress Pinky.
Maybe if I keep my sleeves rolled down, she won't notice the Rolex ...  ;-)