[In this weekly column, GameSetWatch's Danny Cowan rounds up the most popular paid and free iPad gaming applications on the U.S. App Store as of today, with Angry Birds HD, Sid Meier's Pirates! and Mr Giggle HD currently ranking among the platform's top downloads.]

This week's top paid titles are:

1. Angry Birds HD ($4.99)
2. Sid Meier's Pirates! for iPad ($3.99)
3. Angry Birds Seasons HD ($1.99)
4. Angry Birds Rio HD ($2.99)
5. Cut the Rope HD ($1.99)
6. Fruit Ninja HD ($2.99)
7. Captain America: Sentinel of Liberty ($0.99)
8. Trainz Simulator ($0.99)
9. ZombieSmash HD ($0.99)
10. UNO HD ($0.99)

Sid Meier's Pirates! drops to second place in the iPad's sales rankings after topping the charts last week, as Rovio's Angry Birds HD rises up to reclaim first place.

Marvel's Captain America: Sentinel of Liberty enters the charts at seventh place following a recent theatrical release, while N3V's Trainz Simulator falls to eighth after an impressive third-place showing last week.

Here are this week's top free iPad applications:

1. Mr Giggle HD Lite
2. Doors of the Mind: Inner Mysteries HD
3. Mr Giggle 2 HD Lite
4. Angry Birds HD Free
5. Rows 3D for iPad Lite
6. To-Fu: The Trials of Chi HD
7. Angry Birds Rio HD Free
8. Deadlock Online
9. Top Gear: Stunt School HD
10. Allied Star Police

Patryk Palasz's Mr GIggle HD Lite leads the iPad's free charts thanks to the recent release of the successful Mr Giggle 2 HD Lite, which finishes third after debuting at tenth place last week.

HotGen's To-Fu: The Trials of Chi HD takes sixth place after being named Apple's "iPhone Game of the Week," as newcomers Top Gear: Stunt School HD and Allied Star Police debut at ninth and tenth.