What is actually a Significant Achievement for a player in Cricket?
To answer this, I'd say, scoring over 10,000 runs for any player across his/her playing career in any form of International Cricket (ODIs, Tests, T20Is) is something which is taken into consideration to be the so-called Significant Achievement
Sachin Tendulkar, Sourav Ganguly, Rahul Dravid & M.S. Dhoni - 4 players from India
Kumar Sangakkara, Sanath Jayasuriya, Mahela Jayawardene & Tillakaratne Dilshan - 4 players from Sri Lanka
Ricky Ponting - The only player to represent Australia
Inzamam ul-Haq - The only player to represent Pakistan
Jacques Kallis - The only player to represent South Africa
Brian Lara - The only player to represent West Indies
M.S. Dhoni (Mahendra Singh Dhoni) became the 12th Cricketer to achieve this milestone in ODI history. He touched this milestone while playing the 2nd ODI against England @ Lord's, London. He's scored approximately 10,046 runs in 321 matches so far.