best IC design software

im a RF circuit designer looking forward to learn IC design. which software is user friendly and also powerful to design almost anything?
virtuoso analog design environment or something else?

User friendly, powerful, both nice things. But would you
like to have a tool you can afford to pay for? Or is this
Somebody Else's Problem? That and ability to execute
the design flow you're wanting (or compelled) to use
are the two big deals, the rest you can learn to live with.

And when you say you want to learn IC design, the
tool choices also are driven by the emphasis of the
tool vendors - Cadence pretty much dominates the
analog and RFIC spaces, Mentor / Synopsys seems to
win a lot at Big Digital, some smaller players in RFIC
space enjoy some degree of support at RF foundries
but none at mainstream analog or digital ones. And
that (if your interest extends to getting real) is one
other thing, and perhaps first, to start with - who's
going to take your tape-in, and can they offer you
the PDK and database acceptance verification decks
support you will need? This right here is what kills
"free" tools for IC design in any broad usage sense.

i dont care about money at this point of time. looks like cadence virtuoso analog design environment is the best according to you. thanks