I did a benchmark and came up with the following:

    Benchmark: timing 1000000 iterations of eq, lc, re...
        eq:  3 wallclock secs ( 2.76 usr +  0.00 sys =  2.76 CPU)
        lc:  3 wallclock secs ( 2.69 usr +  0.00 sys =  2.69 CPU)
        re:  3 wallclock secs ( 3.13 usr +  0.00 sys =  3.13 CPU)
[download]

You *really* don't need to worry about the differences in speed, unless you're doing this 100000 times or something like that.

Seriously: don't try to optimize things like this. Testing case-insensitive equality is *such* a fast operation that you shouldn't be worrying about it--yes, even in an interactive situation.

Instead worry about Getting It Right. For example, what does your second code snippet do if $type is 'Cr' or 'cR'? Maybe you don't think you need to worry about those things, but I say you should: it's definitely more important than worrying about a couple of milliseconds per every 100000 case-insensitive equality checks.