First of all, the Texans are 8 years old (based on the Jags pulling even at 8-8 versus them in history). In their history, the Texans have been VERY competitive for an expansion team, though not as much so as the Jags and Panthers (compare the Texans to the Bucs, why don't you). In eight years, they've had three winning seasons (if you, like me, count an even record as a winning season). They've had two shots at making the playoffs, only missing them this year because the math was against them. They also have a really slick logo, and were named after a classic AFL team which became the Chiefs. They have an overall record of 49-79.
Second, the Colts being in Indy is irrelevant to their history. Personally, I think their move from Baltimore was actually an important part of their history, but they've had a long history, at least 50 years worth. They've had their ups and downs, were involved in plenty of championship runs (think they lost a couple early NFL/AFL (SB) championships). Oh, and they have a history of playing buck-toothed quarterbacks.

They have an overall record of 441-390-7 (not counting playoffs).
The Jags are 15 years old, and along with the Panthers, are the best expansion franchise in NFL history, going to the AFC championship game twice, the first time in only their SECOND SEASON OF EXISTENCE. Their second trip to the AFC title game was against... a DIVISION RIVAL. How often does that happen, I ask you? In seven years of being in the AFCC, they took the division twice. They hold the distinction of being the only team to beat the Steelers in Pittsburgh twice in one year, and have a 15 year history of brilliant, smash mouth, in your face games against the Steelers in the vein of the NFL of old. They have an overall record of 125-115 (not counting playoffs).
The Titans are a storied franchise. The Oilers were tough AFCC contenders for a number of years, winning the first two AFL championships, and losing two more later on. They've been to the AFC championship game three times, and the superbowl once. In the eight years of the AFCS, the Titans have won the division twice. They were a charter AFL member much like the majority of the AFC, and have just as much history as the rest. They have an overall record of 371-379 (not countign playoffs).