TMPGEnc 4 is pretty much the only tool I use for conversion - apart from VirtualDubMod for some rare cases with cutting/chopping and other editing.

With the DirectShow reader, the only limit for input file formats is what codecs you have installed. Great all-in-one solution for tasks such as -

- Converting DVD videos with a realtime decrypter [AnyDVD] into a Sony PSP or iPod Video format
- Preformatting/reencoding your high-quality videos to a lower quality for quicker upload to YouTube
- Supports AviSynth scripts [via ffdshow] for turning your AviSynth transforming tasks into a new "permanent" or finalized, compatible video format
- And so much more! The possibilities are endless...
- Converting downloaded FLV files to a generic format like MPEG4 [via ffdshow DirectShow Reader]

...even on my old Pentium 4 Prescott 3.2GHz, the encoding speed of this program amazes me. The DivX edition, which I own, is ACTUALLY FASTER than VirtualDub and DivX 6 - i've done my tests, don't listen to that first guy [no offence champ!]. It is true that the DirectShow reader can be slower than native/inbuilt decoding, and can produce undesirable results if say ffdshow has filters enabled - but it's worth it as the flexibility is PHENOMINAL!

HIGHLY recommended! 5/5, 99.9% rating! BUY IT! :D