I don't have one or two names but quite a few.

Most underrated batsmen since I started watching cricket:(or not given the due they really deserved/ records dont tell exactly how great they were)
1. Saeed Anwar (one of the finest leftie ever)
2.Aravinda DeSilva (far better than many present day "GREATS")
3.Arjuna Ranatunga (Superb player,dont go at his build, super batsman)
4.Azharuddin (The artist)
5.Damien Martin
6.Nathan Astle (Capable of playing the way only he could)
7.Graham Thorpe( The Ranatunga of England)
8.Carl Hooper(Probably the best batsman of WI after Lara in the 90s)
9.Gary Kirsten(SA's best batsman in the 90s)
10. Hansie Cronje (some of the astonishing innings against Murali and Akhtar at their peak)

Most Underrated Allrounders

1.Lance Klusener (Smith kicked him out..hate him for that..Cronje got the best out of hum)
2.Brian McMillan( Amazing batsman, bowler and great Slip Catcher)
3.Wasim Akram(was way more capable with bat than his records show)
4.Chris Cairns( his records won't tell, but to me he was the best allrounder I have watched, capable of changing the course in few overs with bat/ball..)

Bowlers:
1. Srinath (was as good as anyone in mid 90s, but that was spinner's time in India)
2.Jason Gillespie
3.This SA bowler of mid 90s who would get Tendulkar out so many times when he was playing at his peak...Fannie DeVelliers.

Wicketkeeper
1.Khaled Masood (Bangladesh. Perhaps one of the finest keepers around, never got his due coz he played for Bangladesh)
2.

over rated:
tendulkar
ganguly
shoaib akhtar
muralidharan

underated:
kallis
afridi
gautam ghambir
saqlain mustaq

Overrated 

1. Jacques Kallis

2. Rahul Dravid

They have good individual records but to me both of them aren't real match winners.

 

Underrated

1. Steven Fleming (he is awesome batsman....and a great captian too)

2. Lance Klusener ( Best All rounder- its sad that We didn't get chance to watch him playing more Int'l cricket games, IDK... may be because of quota system in SA or any other resons...

3. Ross Taylor (He'll be a star in future....)

I think that most of the players from NZ are underrated..

Not quota system. Graeme Smith didn't like Klusener personally, and he made sure that Klusener isn't picked at all, thus prematurely ending career of one of the would be finest allrounders. QA genuine one and a true match winner as well.

Overrated:

Sachin Tendulkar (he does not totally deserve the fame he has)

Rahul Dravid (he probably did play well during his days, but he has not lived up to expectations; it is waste to still expect from him)

I do not think Jacques Kallis is overrated; he is the match winner. You can not win the match all the times. Neither is Muralitharan.

Underrated:

Chris Cairns

Saqlain Mustaq

Stephen Flemming (oh my god, I love him when he gets going)

IMO, Chanderpaul, Sangakkara, mortaza, DeSilva, Chaminda Vass and Mohammad Yousuf are the most under-rated players...
Similarly, Most of the Indian batsmen, Flintoff and Brett Lee are the most over-rated players...

Most under rated:
1. Chaminda vaas
2. Danish kaneria
3. Shiva naraen chanderpaul
4. Daniel vettori
5. Michael bevan and hussey

Most over rated:
1. Mahendra singh dhoni
2. Shahid afridi
3. Andrew symonds
4. Ram naresh sarwan
5. Jaques kallis

If Sachin Tendulkar is overrated, Nepal is the richest country in the world, Prachanda is an epitome of non-violence, We all walk on water and there is arid land in Mars that I own.

Get over the India hating mentality u people. Think outside the box if u can. Doesn't matter how much people in Nepal hate Tendulkar bcoz of his nationality, he is what he is and that u know when u go anywhere else in the world but Nepal.

underrated:

Michael Vaughan (class player..fter tendulkar and lara)

Fleming

Stuart MacGill (overshadowd by warne)

dSilva

Over Rated:

Dhoni

sohaib akthar

 

 

I do not know what does under or over rated means..... and what are the basis of some players being tagged as under or over rated here.....

If under or over rated implies to the media hype..... yes there are some players who are much hyped especially some Indian youngsters and English cricketers.... Thats simply beacuse they have a strong media presence in their country... It would happen everywhere...

In my view there are really some players who are unlucky like Stuart McGill who was over shadowed by All time great Shane Warne.... Michael Vaughan is a great test (BUT NOT IN ODI)batsman but I do not consider him under rated as no any english cricket fans or media will under rate him..... In ODI I think Laxman was underrated... Jaysurya was underrated as a bowler in both formats.... Akram was underrated as batsman....

Regarding overrating of players.. I can genuinely see some Indian youngsters being over rated... there are a lot of them in One Day team especially....but I never think Sachin/Sourabh/Dravid/Shewag  being overrated as test or ODI players... they deserve the credit.....  Dhoni isnt still a test great but not an overrated one day player or leader... Sohaib Akhtar is a bit over rated given the number of matches he have played but he is still a fantastic player when physically and mentally fit....

younis khan, daniel vettori...and chris gayle are also very underrated

the most over rated player now is Michael Hussy, his test average was more than 90 in the beginning but now it is almost below 60.