Heh I am a "Veteran" Beil tan player ( 3 years makes me a vet right?) and a semi vet Aliatoc (only 2 years here)....and my friend constantly owns me with his ulthwe...so i thinkn i can offer a bit..
if you prefer shooty go for the aliatoc, they are a very shooty list with all those rangers.
biel tan can also be shooty what with taking dragons and reapers as troops. but if you arent too into the in ur face HtH type id go for Aialiatoc.
with the rangers i do some thing liek this....
8 squads of guys with sniper rifles (yeah im nuts and i dont expect anyone else to do this) and reapers and walkers as the static fire bases (though walkers do walk around).
but they still need some sort of fast response units, i use 2 storm guardin squads in serpents with 2 flamers and warlock with destructor, serpents have lances. walkers got scatters.
ill toss in vypers as well if points allow, oh and a seer with just guide and runes of witnessing.
the fire base does exactly as it sounds it stayes and fires from cover , or out in open if neccessary, oh and a fire prism in there for soem bigger boom.. and the guardians go and are a reactionary unit they assault only when neccessary and are usually there just for the flamer templates.
so basically make a strong fire bas and have some fast reactionary units available.
Beil tan, well i run a serpent rush with a fire base that is the wlakers reapers prism and 5 rangers... the rest are 3 hth units and draogns runnin up to say hullo. works well for me, good for rolling up one flank and still being able to fire down to the other flank.