Lions head coach Warren Gatland will not announce his squad until the end of next month, but Roberts and Ireland's Brian O'Driscoll are already being widely tipped as the midfield partnership. If that happens, it would reunite them four years after they started the first and second Tests against South Africa, with Roberts going on to be named Lions player of the series.
"It (the 2009 tour) was a huge stepping stone in my career, and I look back on it with very fond memories. It was certainly the best tour I have ever been on as a player," Roberts said. "To play on that stage is the ultimate as a rugby player. It doesn't get any better."
He added: "To make friends on tour with guys from other countries, guys you have grown accustomed to playing against, and seeing four sets of fans come together is a special experience.
"My old man went out in 2009 and made a lot of friends from England, Scotland and Ireland. It's unique in that way for players and fans."
With this season's 6 Nations Championship now over, Lions selection will dominate rugby's agenda. Gatland looks set to unveil his tour party just a few days after the Heineken Cup semi-finals take place on April 27/28.
Roberts, his Wales centre colleague Jonathan Davies, O'Driscoll and England's Manu Tuilagi are widely expected to fill the centre berths.
"I think every player will tell you that the Lions has been in the back of their minds since the start of the season," Roberts said. "It's there, it is itching away in the back of your head, and it is now within touching distance. Everyone has a chance to stake their claim.
"All you can do is go out and perform on the pitch every week, giving your all. If that's good enough then great, if it's not good enough then that is the way it is.
"It is up to the coach who he wants to select, at the end of the day, and what sort of players he wants to take on tour."