We have had our VF5/50 for about 14 months now and are still in love with it. Here is what we got for options:
AAG1 - Auto Air Gun - inexpensive and nice to have for hi-feeding pockets
TSC300-B & AF - through spindle coolant & aux filter - not a must have, but it sure is nice at times. We often profile mill the outside of tallish parts (2"-3") and the part shadows the tool from the normal coolant stream during portions of the cut. The TSC allows us use those endmill holders that flood the periphery of a non-coolant fed tool.
HIL - high intensity lighting - well worth the money, for my aging eyes.
ENET/HD/USB - I say this is a must have if you program off line. Map the HDD on the VF and set your CAM software up to post right to it. You can run the program on the VF right from the HDD. If you make a change in your CAM software, you just repost, hit reset on the VF and cycle start.
VQCPS - tool & work probing, plus macros, coord rotation & scaling for $5k? You would be crazy not to get this.
4AXBL - 4th axis drive & wiring - seemed like $1600 well spent, will will get a 4th sooner or later and in theory, should be able to plug it in and go.
PFDM - early power failure detection for $500, if it prevents one crash it's paid for itself.
Get the extra M-codes. Make sure they are extra. They will advertise "8" when really you get 4 more. They just add to the 4 you already bought. I needed a lot of M-codes for my VF-3 for hydraulic clamping and a rotary indexer. For the probe, it should be wireless. Mine works great. You just have to watch close for when the batteries go bad. If you need 50 taper, then you must be doing some hefty machining. I got the HRT-320FB, which is the beefiest indexer out there. At the time I got mine, there was only one other one at least in the US. I can elaborate more later on the indexer, it is a must have though.
Our shop's VF-11 had the high intesity lighting and i didn't like it. I say had because eventually we had a part big enough that I had to remove the lights. They won't be going back in. However i agree with pdoherty in saying that ethernet is a must. And although it doesn't have it i wish we had the expanded memory