Jason Mesnick and Melissa, The Bachelor

Monday's ratings round-up:

8 pm/ET
The two-hour season finale of The Bachelor: Flip-Flop Edition was the night's most watched program, averaging 15.45 million total viewers — the series' best audience since Bob chose Estella in November 2003. CBS' sitcombo secured second, with Big Bang Theory holding steady at 10.94 mil and How I Met Your Mother delivering 11.08 mil.

24's White House siege averaged 11.1 mil over its two-hour run, and gained viewers each half hour. Chuck (6.6 mil) inched up a bit from last week's all-time low.

9 pm
Two and a Half Men trailed The Bachelor with 15.42 million viewers (up 500K from its last fresh outing), while lead-out Rules of Engagement returned to 11.86 mil, which was good for third in its time slot. Heroes matched last week's 7 mil.

10 pm
Proving that car-crash television can work, The Bachelor: After the Rose drew its largest audience ever — 17.5 million viewers. CSI: Miami settled for second with 13.3 mil, down 400 thou. Medium took a big hit, slipping 14 percent to 7.28 mil.

Late Night
The premiere of Late Night with Jimmy Fallon gave NBC its highest-rated Monday Late Night in more than three years (since Jan. 16, 2006). It also bested CBS' Late Late Show and ABC's Jimmy Kimmel by margins of 35 percent and 17 percent, respectively.