Arcade. I like his personality and think he'd be the funnest and most interesting to have around.

veronica and arcade

Let me just add christine cuz she is super well trained, is related to veronica and the BOS, and will tell when youre in caution mode.

The only ones I use are veronica and cass

In order: Boone, Arcade, Raul. Better yet, all three at once for the lol's.

It depends:
Personality wise:
Cass: Love her mean drunk sarcasm.
Veronica: More irony than sarcasm.. Simply like her fun comments (which is why I never like her personal quest... no matter what path you chose it will always destroy her future so to speak). Also because of DM possibly the companion with the most background... but Cass has ties to the previous titles.
Arcade and Raul are also kinda fun..

Strategy:
Boone: If I play NCR, either as sniper support.... or as spotter with Ed-E (keep Ed-E away from the enemies in wait mode... and it becomes a great sniping tool)
ED-E: For the above mentioned reasons and with LR the best allround companion
Veronica: With Pushy or a Balistic fist combined with a energy weapon... Trouble for your foes..
Lilly: Support if you use a lot of stealth boys... (for example if you want to silently eliminate BOS), again in waiting mode.
Rex: Pretty useless.., Arcade: Good allround ew guy, Raul: With a nice revolver decent gun support, Cass: Utter crap... no matter what weapon I give her.. she will eat more ammo than a minigun on steroids... But like I stated I like her whining.

Eddie and Boone when I need some combat support. Veronica is probably my favorite. Lots of fisting damage and witty comments. Love her. Also like how her story ties into DM.

Arcade and Raul were my BFF's. Veronica was pretty awesome too. I adored Dean in Dead Money as well, I was sad when I couldn't keep him

I just can't stand Arcade and Raul's defeatist dialoge. I always stayed with Boone but if I had to choose I will go with Veronica, her personality just goes of the charts, I always had a good time listening to her, its really fun and combat effective. Didn't stay long with cassidy. Lily...well, I love the orkish dialoge but the noise she does when going stealth it's really anoying. Wish the mojave ED-E was as fun or expresive as the divide ED-E (stealthy bleeping FTW), who couldn't love that little boy?

Raul is my favorite followed closely by Rex. I've used Cass before but she tends to grate on my nerves sometimes, and Veronica I can take or leave. EDE I didn't much care for, except for his twin in OWB. I haven't used any of the others, so I can't comment on them.

EDIT: Forgot all about Arcade, I'd put him Between Rex and Cass in terms of who I'd rather run around with.

Boone. Although haven't gone through all the loyalty quests yet.

Cannot get Arcade to give me his loyalty quest and sort of pissed off about how I screwed myself with Veronica's. But Boone is my favorite. A good ol' fix-em up person.

Oh and Ed is fun. Rex seems cool but he/she/it goes running off everytime and dies in a hit or two. So now he gaurds my home.

Cass.. well, is cass. And just met Raul, but I not really interested in his story it seems. And no.. not goul hate

BTW, why is there no Goul town in New Vegas?

Boone. I simply like his views and sometimes he reminds me of.. me.