Get both
I have a Virus C and a Fantom X7 and i love them both but i would never compare them because they are very different synths. The Virus is a VA (virtual analog) that built it sounds with oscilators (like the analog synths does) while the Fantom X uses sampled sounds. I guess it all depends on what type of sounds you want and how much tweaking/programming you will be doing. The Virus is great for trance and acid leads, basses, pads and sound effects. I don?t know about the TI compared to the C but i guess it?s great for the same kind of sounds just better. The Fantom X on the other hand really shines when it comes to acustic instuments like acustic guitars and pianos but it does nice trance and dance oriented sounds too and has some nice drums as well. Besides that it has a sampler and a 16 track MIDI / 8 track audio sequenser (only keyboard versions) and some nice effect including a 3 band mastering compressor and it can be upgraded with up to 4 SRX expansion boards, 1 Gb RAM for longer sampling time and 1 Gb flash RAM for extra storage. I guess the Fantom is best for allround purpose and the Virus is the best for analog sounds. They actually compliment eachother very well. The best advice i can give you is to go and play with them both in your local music shop before you decide...